Fix an error related to Hammer.JS on client startup on pages that define
a global variable called `define`, which is part of Require.JS. Hammer's UMD
bundle does not set `module.exports` in this case, so modules that import it
get an empty object back.

Fix the issue by making sure that any reference to `define` inside
bundles evaluates to undefined (assuming there is no local variable
within the module with that name).

This fixes an issue where clicking "Annotate" failed to open the sidebar
on BBC News articles (eg. https://www.bbc.co.uk/news/world-52144390).

Fix annotation and thread vertical rhythm and layout

Adjust some HTML semantic structural elements

Use SVG icons for adder toolbar

Replace `module.exports` with ES exports

Make the icons for Annotate and Highlight in the adder toolbar
consistent with the sidebar by replacing the icon font icons with the
`SvgIcon` component.

Adjust the vertical margin between the icon and the label slightly as
the new Highlight icon and label look too close otherwise.

Move SvgIcon component to `src/shared/` in preparation for re-use in the
"annotator" part of the application.

Change `cross-origin-rpc.js` to use ES exports instead of `module.exports`
for consistency with other modules.

Also update documentation in `service-context.js` to use ES exports.

Separate out icon definitions from `SvgIcon` component

Improve documentation per PR feedback.

Validate prop types in tests

Remove remaining implicit jQuery imports

Tighten up display of headers for collapsed replies in threads

Replace the hardcoded set of available icons in `svg-icon.js` with a
`registerIcons` function which is called by the application at startup
to register the icons that should be available for use.

This will enable us to re-use the `SvgIcon` component in the "annotator"
part of the client or other applications (as part of our UI component
library) which use a different set of icons.

The lms application currently has a different solution for this in its
`SvgIcon` implementation which requires the icon markup to be passed
each time the component is used. On reflection, I think that passing
just the name at the point of use is going to be more convenient in app
code and when writing tests.  It also avoids the need to validate the
markup is from a trusted source on each use.

- Remove obsolete comments in `src/sidebar/test/bootstrap.js` about
  Angular using the full version of jQuery. This no longer applies.

- Remove the last few uses of the `$` global variable to reference
  jQuery and replace it with an explicit import. This will make it
  easier to identify the remaining parts of the app that are still using
  it.

This adds basic runtime verification that mocked components are called
with types that are compatible with what the real component expects.

This turned up one existing issue with use of `MenuSection` by
`UserMenu`, where conditional rendering would cause the prop type check
to fail.

For consistency with other tests, use `mockImportedComponents` so that
an issue with an imported component doesn't cause a cascade of failures
in the unit tests for these components.

Only create one highlight element for adjacent text nodes

Replace angular-mocks in service tests

Bump @sentry/browser from 5.15.0 to 5.15.4

Bumps [@sentry/browser](https://github.com/getsentry/sentry-javascript) from 5.15.0 to 5.15.4.
- [Release notes](https://github.com/getsentry/sentry-javascript/releases)
- [Changelog](https://github.com/getsentry/sentry-javascript/blob/master/CHANGELOG.md)
- [Commits](https://github.com/getsentry/sentry-javascript/compare/5.15.0...5.15.4)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bump autoprefixer from 9.7.4 to 9.7.5

Bumps [autoprefixer](https://github.com/postcss/autoprefixer) from 9.7.4 to 9.7.5.
- [Release notes](https://github.com/postcss/autoprefixer/releases)
- [Changelog](https://github.com/postcss/autoprefixer/blob/master/CHANGELOG.md)
- [Commits](https://github.com/postcss/autoprefixer/compare/9.7.4...9.7.5)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bump browserify from 16.5.0 to 16.5.1

Bumps [browserify](https://github.com/browserify/browserify) from 16.5.0 to 16.5.1.
- [Release notes](https://github.com/browserify/browserify/releases)
- [Changelog](https://github.com/browserify/browserify/blob/master/changelog.markdown)
- [Commits](https://github.com/browserify/browserify/compare/v16.5.0...v16.5.1)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bump dom-seek from 4.0.3 to 5.0.1

Bumps [dom-seek](https://github.com/tilgovi/dom-seek) from 4.0.3 to 5.0.1.
- [Release notes](https://github.com/tilgovi/dom-seek/releases)
- [Commits](https://github.com/tilgovi/dom-seek/compare/v4.0.3...v5.0.1)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

When highlighting a run of adjacent text nodes, wrap the group of
adjacent text nodes in a single `<hypothesis-highlight>` element rather
than wrapping each text node separately. Adjacent text nodes may be
created if:

 - A sub-range of the text is highlighted by Hypothesis, and the
   highlight is later removed, for example when switching groups.
 - The text nodes were generated programatically by JavaScript rather
   than by the browser's HTML parser

For screen reader users, this reduces the number of "annotation
start"/"annotation end" comments they will hear in this scenario. It is
also likely to benefit other code which interacts with highlighted text.

As part of the migration away from Angular, replace the use of
angular-mocks for constructing service instances in tests.

 - For tests that only have one or two dependencies, call the service
   constructor directly
 - For tests that have many dependencies, enough that the order could be
   easily mixed up if calling the constructor directly, re-use the
   `Injector` class which is used to wire up services in the real
   application

Several of these tests relied on Angular's built-in `$rootScope`
service. Use of this should go away entirely soon, but for this commit,
just replace it with a minimal mock - either an object with stubs or an
`EventEmitter`.

Reformat with Prettier v2

Even after adjusting the configuration to match Prettier 1.x output as
closely as possible, some breaking changes did require running `make
format`.

Update the configuration so that it matches our other repos and is as
close as possible with Prettier v2.x to Prettier v1.x output.

Add translation map for specific host-config values

add `type-coercion.js` util with 4 methods. These are used on incoming the host-config values `openSidebar` and `requestConfigFromFrame` which may have an incompatible type upstream (via3) from what the client expects.

- toInteger
- toObject
- toString
- toBoolean

These methods coerces specific values into types so that downstream (client) methods can make assumptions. This is part of the prep work to support via3 which will eventually only export strings values in the config.

Bumps [@octokit/rest](https://github.com/octokit/rest.js) from 17.1.1 to 17.1.4.
- [Release notes](https://github.com/octokit/rest.js/releases)
- [Commits](https://github.com/octokit/rest.js/compare/v17.1.1...v17.1.4)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>