In preparation for updating the fake PDFViewerApplication to match changes
in PDF.js' interface, refactor the fake.

 - Rewrite old-style classes as ES6+ classes

 - Replace object literals for `PDFViewer` and `PDFPageView` fakes with
   actual classes that have JSDoc comments pointing to the real class's
   definition

Convert PDF anchoring code to JS

Remove changelog

Update script to authenticate using the new API documented at
https://github.com/octokit/rest.js#authentication

Since we're using GitHub's Node REST client already, use it to create
the GitHub release instead of making a "manual" HTTP request.

The client deployment process currently involves a commit to master to
update the CHANGELOG and version in package.json. This creates a problem
when trying to deploy a build that is not the latest release of master.
It also creates other failure modes that are not really necessary.

As a first step to resolving this problem, remove the changelog in the source
tree. The notes attached to the GitHub release will suffice, together
with any handwritten updates that developers post in #changelog in
Slack.

 - Remove CHANGELOG.md and scripts to generate it from source tree
 - Remove changelog references from build process
 - Change GitHub release script to generate the change list directly
   instead of reading it from CHANGELOG.md
 - Change the client's dev server to use the Code of Conduct instead of
   the changelog as a text source for the test page

Bump @babel/core from 7.1.6 to 7.2.2

Bump @babel/preset-env from 7.1.6 to 7.3.1

Bumps [@babel/core](https://github.com/babel/babel) from 7.1.6 to 7.2.2.
- [Release notes](https://github.com/babel/babel/releases)
- [Changelog](https://github.com/babel/babel/blob/master/CHANGELOG.md)
- [Commits](https://github.com/babel/babel/compare/v7.1.6...v7.2.2)
Signed-off-by: dependabot[bot] <support@dependabot.com>

Bumps [@babel/preset-env](https://github.com/babel/babel) from 7.1.6 to 7.3.1.
- [Release notes](https://github.com/babel/babel/releases)
- [Changelog](https://github.com/babel/babel/blob/master/CHANGELOG.md)
- [Commits](https://github.com/babel/babel/compare/v7.1.6...v7.3.1)
Signed-off-by: dependabot[bot] <support@dependabot.com>

Bump eslint from 4.19.1 to 5.12.1

Bump @octokit/rest from 16.10.0 to 16.13.4

Bump proxyquire from 1.8.0 to 2.1.0

Bumps [eslint](https://github.com/eslint/eslint) from 4.19.1 to 5.12.1.
- [Release notes](https://github.com/eslint/eslint/releases)
- [Changelog](https://github.com/eslint/eslint/blob/master/CHANGELOG.md)
- [Commits](https://github.com/eslint/eslint/compare/v4.19.1...v5.12.1)
Signed-off-by: dependabot[bot] <support@dependabot.com>

Bump exorcist from 0.4.0 to 1.0.1

Merge pull request #912 from hypothesis/dependabot/npm_and_yarn/babel-plugin-angularjs-annotate-0.10.0

Bump babel-plugin-angularjs-annotate from 0.9.0 to 0.10.0

Bumps [proxyquire](https://github.com/thlorenz/proxyquire) from 1.8.0 to 2.1.0.
- [Release notes](https://github.com/thlorenz/proxyquire/releases)
- [Commits](https://github.com/thlorenz/proxyquire/compare/v1.8.0...v2.1.0)
Signed-off-by: dependabot[bot] <support@dependabot.com>

Bumps [@octokit/rest](https://github.com/octokit/rest.js) from 16.10.0 to 16.13.4.
- [Release notes](https://github.com/octokit/rest.js/releases)
- [Commits](https://github.com/octokit/rest.js/compare/v16.10.0...v16.13.4)
Signed-off-by: dependabot[bot] <support@dependabot.com>

Bumps [exorcist](https://github.com/thlorenz/exorcist) from 0.4.0 to 1.0.1.
- [Release notes](https://github.com/thlorenz/exorcist/releases)
- [Commits](https://github.com/thlorenz/exorcist/compare/v0.4.0...v1.0.1)
Signed-off-by: dependabot[bot] <support@dependabot.com>

Bumps [babel-plugin-angularjs-annotate](https://github.com/schmod/babel-plugin-angularjs-annotate) from 0.9.0 to 0.10.0.
- [Release notes](https://github.com/schmod/babel-plugin-angularjs-annotate/releases)
- [Changelog](https://github.com/schmod/babel-plugin-angularjs-annotate/blob/master/CHANGES.md)
- [Commits](https://github.com/schmod/babel-plugin-angularjs-annotate/compare/v0.9.0...v0.10.0)
Signed-off-by: dependabot[bot] <support@dependabot.com>

Update Babel and code coverage tooling

Configure babel-plugin-istanbul to avoid adding instrumentation to JS /
CoffeeScript files under directories named "test".

See https://github.com/istanbuljs/babel-plugin-istanbul#ignoring-files

Upgrade the dependencies used for adding dependency injection
annotations to Angular components and services, and the libs used for
code coverage reporting.

- Replace browserify-ngannotate with babel-plugin-angularjs-annotate.
  The repo's README states that the former is unmaintained and the
  latter is the successor.

- Replace browserify-istanbul + isparta + karma-coverage for code
  coverage reporting with babel-plugin-istanbul +
  karma-coverage-istanbul-reporter.

  babel-plugin-istanbul is the recommended method for instrumenting code
  using current versions of Istanbul. The karma-coverage reporter uses
  an old version of Istanbul. karma-coverage-istanbul-reporter is
  a reporter that uses the current version and is intended to be used
  alongside the Babel plugin.

- Upgrade karma and karma-browserify

This adds support for transpiling newer JS language features (ES2016+) and will
make it easier to update going forwards.

Decisions over what features to transpile for backwards compatibility
are controlled by browser coverage queries. See the browserslist docs [1] for
details of the query format.

[1] https://github.com/browserslist/browserslist

Bump wrap-text from 1.0.7 to 1.0.8

Bump eslint-plugin-mocha from 4.12.1 to 5.2.1

Bump angular-sanitize from 1.7.5 to 1.7.6

Bump karma-browserify from 5.3.0 to 6.0.0

Bump diff from 2.2.3 to 4.0.1

Bump gulp-sourcemaps from 1.12.1 to 2.6.4

Bump check-dependencies from 0.12.3 to 1.1.0

Bump aws-sdk from 2.394.0 to 2.395.0

Bump autoprefixer from 6.7.7 to 9.4.7

Bumps [eslint-plugin-mocha](https://github.com/lo1tuma/eslint-plugin-mocha) from 4.12.1 to 5.2.1.
- [Release notes](https://github.com/lo1tuma/eslint-plugin-mocha/releases)
- [Changelog](https://github.com/lo1tuma/eslint-plugin-mocha/blob/master/CHANGELOG.md)
- [Commits](https://github.com/lo1tuma/eslint-plugin-mocha/compare/4.12.1...5.2.1)
Signed-off-by: dependabot[bot] <support@dependabot.com>

Bumps [angular-sanitize](https://github.com/angular/angular.js) from 1.7.5 to 1.7.6.
- [Release notes](https://github.com/angular/angular.js/releases)
- [Changelog](https://github.com/angular/angular.js/blob/master/CHANGELOG.md)
- [Commits](https://github.com/angular/angular.js/compare/v1.7.5...v1.7.6)
Signed-off-by: dependabot[bot] <support@dependabot.com>