Add theme option addModeClass (for language-aware themes)
Debounce calls to ProjectManager._renderTree.

This is a possible fix for #9851. In my tests, this can cause a
dramatic speed up when lots of filesystem changes cause the tree
to be continuously rerendered.

I chose 100ms as the debounce time because that seemed quick enough that
users will not be waiting for their actions to be reflected in the tree.
Fix WorkingSetView test based on review feedback.
Workaround for #10124: change the title on close.

On Mac/OSX alert causes system modal dialog which prevents any interaction with
the browser and navigating away. This was causing unit tests to fail.

So instead of showing alert, change the title of the document to indicate that
the Live Preview session was closed. A more clear UI/UX definition is needed
for definitive solution.
Address review comments.

    - Exclude failing test.
    - Add full screen overlay on Live Preview close in browser.
Use Jasmine's `waits` function instead of my own.

Also fixes JSHint error.
Merge pull request #10039 from MarcelGerber/themes-mode-class

Add theme option addModeClass (for language-aware themes)
restore whitespace
Merge pull request #10120 from adobe/dangoor/9851-debounce-render

Debounce calls to ProjectManager._renderTree.
Merge pull request #10129 from adobe/kai/fix-mb-livedev-test-failures

Workaround for #10124: change the title on close.
Revert changes for terminating Tern worker on quit.
Merge pull request #10135 from adobe/rlim/revert-worker-termination

Revert changes for terminating Tern worker on quit.