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
Initial checkin of HTMLInstrumentation
Add dom element highlighting.
Updated comments
Store parse information in separate object so it doesn't get lost when the editor is destroyed.
Merge branch 'master' into html-highlight
Highlight from HTMLDocument
Merge branch 'master' into html-highlight
Make HTML highlight work after saving document.
refactor unit tests. add new tests for warnings when a response is not handled or was already handled.
Typos-Я-us
Fixing the adjust font restore scroll and adding unit tests
Updated to check for language id instead of mode
Refactored QuickOpen to use language ids
Removed an obsolete space
Added backwards compat code
Fixes after first review