Standardize text colors

- Also tighten padding as it was a little loose

Add deprecation notice for IE11 browsers

Remove unused/unnecessary SASS vars and mixins

- Remove unnecessary clearfix in annotation-header. We don't use floats
  in the layout of annotation threads or annotations any more.

- Remove unused variables

- Remove an unused mixin in `forms.scss`

Rectify infinite load on single-annotation, stream views

Bump mocha from 7.1.2 to 7.2.0

Bump karma from 5.0.8 to 5.0.9

Bump terser from 4.6.13 to 4.7.0

Bump fetch-mock from 9.9.0 to 9.10.1

Bump preact from 10.4.1 to 10.4.4

Fix installing tox

Update 3 config keys

- `allowLeavingGroups`
- `groups` when used with “$rpc:requestGroups” value
- `requestConfigFromFrame`

Our scripting automatically installs tox in pyenv so you don't have to
install tox manually or system-wide. Unfortunately it wasn't working:
the installed tox doesn't appear on your PATH until you run a
`pyenv rehash`

Bump chance from 1.1.5 to 1.1.6

Remove `OAUTH_TOKENS_CHANGED` event

Remove unused diff-match-patch dependency

We don't use this package directly any more, although there is still a
transitive dependency on it via dom-anchor-text-quote.

Bumps [aws-sdk](https://github.com/aws/aws-sdk-js) from 2.679.0 to 2.683.0.
- [Release notes](https://github.com/aws/aws-sdk-js/releases)
- [Changelog](https://github.com/aws/aws-sdk-js/blob/master/CHANGELOG.md)
- [Commits](https://github.com/aws/aws-sdk-js/compare/v2.679.0...v2.683.0)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [@octokit/rest](https://github.com/octokit/rest.js) from 17.9.1 to 17.9.2.
- [Release notes](https://github.com/octokit/rest.js/releases)
- [Commits](https://github.com/octokit/rest.js/compare/v17.9.1...v17.9.2)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [preact](https://github.com/preactjs/preact) from 10.4.1 to 10.4.4.
- [Release notes](https://github.com/preactjs/preact/releases)
- [Commits](https://github.com/preactjs/preact/compare/10.4.1...10.4.4)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [terser](https://github.com/terser/terser) from 4.6.13 to 4.7.0.
- [Release notes](https://github.com/terser/terser/releases)
- [Changelog](https://github.com/terser/terser/blob/master/CHANGELOG.md)
- [Commits](https://github.com/terser/terser/compare/v4.6.13...v4.7.0)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [chance](https://github.com/chancejs/chancejs) from 1.1.5 to 1.1.6.
- [Release notes](https://github.com/chancejs/chancejs/releases)
- [Commits](https://github.com/chancejs/chancejs/compare/1.1.5...1.1.6)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [mocha](https://github.com/mochajs/mocha) from 7.1.2 to 7.2.0.
- [Release notes](https://github.com/mochajs/mocha/releases)
- [Changelog](https://github.com/mochajs/mocha/blob/master/CHANGELOG.md)
- [Commits](https://github.com/mochajs/mocha/compare/v7.1.2...v7.2.0)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [karma](https://github.com/karma-runner/karma) from 5.0.8 to 5.0.9.
- [Release notes](https://github.com/karma-runner/karma/releases)
- [Changelog](https://github.com/karma-runner/karma/blob/master/CHANGELOG.md)
- [Commits](https://github.com/karma-runner/karma/compare/v5.0.8...v5.0.9)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [fetch-mock](https://github.com/wheresrhys/fetch-mock) from 9.9.0 to 9.10.1.
- [Release notes](https://github.com/wheresrhys/fetch-mock/releases)
- [Commits](https://github.com/wheresrhys/fetch-mock/compare/v9.9.0...v9.10.1)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>