Fix Live CSS with an iframe element
Added unit test, fixed NetworkAgent
Add another unit test, Rename simple2.* test files
Fix RemoteAgent and ScriptAgent
Fix Live CSS bug
Fix unit tests
Cleanups to status bar language-switcher:
* Make LanguageManager the official public API that is used to set per-file
overrides, rather than proxying through Document objects - remove Document.setLanguageOverride()
* Clear path overrides when switching projects, so it's more obvious that
it's not something that gets persisted across sessions
* Simplify how JS Code Hints listen for language updates: remove dependency
on "currentDocumentLanguageChanged" event; remove unneeded extra 'if' tests
Add "Set as Default" menu item to status bar language switcher -- adds a
permanent file extension mapping to preferences, based on the current
file's path-specific language override (if any) and its file extension.
* Gray out status-bar language switcher's "Set as Default" item if the doc's
current language is already the default (i.e. there's no path-specific override).

DropdownButton changes:
* Support disabled items
* Fix bug #8433 (Page Up/Down work oddly) - Only wrap around to other end
of list when using arrow keys. Page Up/Down 'stick' at start/end of list
instead (so they will act like Home/End when there's no scrollbar).
* Add Home/End key support
add pref to prevent js code hints on dot
update unit tests for extension manager keepFile flag
handle live preview for docs not in working set
allow .xhtml files for live preview
jsdoc info
refactor to use a _removeHighlight() method
more changes for code review
Code review fixes:
* Use .hasClass() instead of .is() where possible
* More succinct math operators in DropdownEventHandler._tryToSelect()
* Document language-change events
* Improve some more JS code hints docs
Merge remote-tracking branch 'upstream/master' into live-css-iframe
Fix JSDoc, unify clearCSSForDocument with reloadCSSForDocument
Fix language switcher persistence to work when no custom file extension
mappings are set yet - don't leave default value of pref undefined.

Clarify two other cases of definePreference() calls where we really *do*
want the default value to be undefined by passing it explicitly.

Also: add TODOs for unused Session arg in JS code hints.