Fixes #2608 (QuickOpen shows red on first use) and also makes QuickOpen more responsive on
large projects by not immediately invalidating the cached file list.
Reset StringMatcher caches when file list is retrieved.

Now that the file list in Quick Open is more lazily retrieved, we should
clear out the old StringMatcher caches to avoid possibly stale data
sticking around even after the file list has arrived.
Use language id
undefined live browser ids are never removed from list, so don't add them
Updated comments
refactor unit tests. add new tests for warnings when a response is not handled or was already handled.
Fixing the adjust font restore scroll and adding unit tests
use language instead of file extension to choose live dev document type
Merge branch 'master' into jasonsanjose/issue-3307

Conflicts:
	src/LiveDevelopment/Documents/HTMLDocument.js
Merge pull request #3312 from adobe/jasonsanjose/issue-3307

Use Language instead of file extension to choose live dev document type
Merge pull request #3270 from WebsiteDeveloper/UsageOfLanguageId

Use language id instead of CodeMirror mode in CodeHintManager
move timeout reset to afterEach()
Move the JSLint strings
change live dev unit test assumptions now that the initial loaded document can contain in-memory changes.
Merge pull request #3294 from adobe/jasonsanjose/middleware

Update StaticServerDomain unit tests
Merge pull request #3272 from adobe/randy/live-browser-id-leak

Fix live browser id array leak
Merge pull request #3316 from adobe/jasonsanjose/issue-3307

Change live development unit test assumptions after HTML highlight changes
Fixes after first review
Add unit tests for HTML Instrumentation.
Update DOMHelper to support uppercase tag names.
Add one more empty tag -- wbr.
Add code to ignore invalid closing empty tags.
Update to CodeMirror (not quite latest due to a recent injection)