Topcoat-style toolbar: dark vertical strip on right. Hides the old
horizontal "titlebar" unless in-browser mode. Vertical toolbar retains the
original "#main-toolbar" id so extensions that add icons will generally
continue to just work. Most extensions that add horizontal toolbars will
break, however.
- Update the update icon for new toolbar
- Rename Resizer.forcemargin to forcepadding to reflect new panel layout
- Remove unneeded styles (z-index on .content & #main-toolbar,
- Move main-toolbar icon styles next to other main-toolbar styles
Merge remote-tracking branch 'origin/master' into pflynn/topcoat-toolbar

* origin/master: (37 commits)
  Fix unit tests to account for 2feef29
  update unit tests now that shell mode is a default language
  Fixes after second review
  remove extra StringUtils
  use emdash on mac only
  add licenses
  Fixes after first review
  Fix after review
  A bit cleanup
  revert change to unit test fixture again
  revert change to unit test fixture
  It now passes editor as a parameter using run and all the tests run in one window
  Fixes after second review
  Collect style tags the same way as we collect script tags. ie. collect everything up to the end tag in one step.
  Fixes after review
  Correct fix for gutter padding issue in #3211
  Fix running dev & user extension unit tests. After pull #3334 only core (extensions/default) extensions show up in the spec running UI.
  keep html title for in-browser. update unit tests.
  Fixed replacement when currently in Entity
  Minor text fixes
  ...

Conflicts:
	src/document/DocumentCommandHandlers.js
	src/extensions/default/RecentProjects/main.js
	test/spec/DocumentCommandHandlers-test.js
Alternative center panel layout: use position left/right rather than
left/right padding. Slightly simpler and possibly (don't know until testing)
may be faster too.
Code review cleanups:
- add "in-appshell" body style, mutually exclusive with "in-browser"
- use symbolic constants for more colors
- rename Resizer's "forcepadding" to "forceleft" to reflect new layout
- remove unneeded qualifier on "#main-toolbar" selector
- remove unused padding on Live Preview icon rule (overrided by other rules)
- improve docs
Prevent titles of bottom panels (which use the .simple-toolbar-layout class) from overlapping the right-hand toolbar
Code review: tweak comment
Merge pull request #3381 from adobe/pflynn/topcoat-toolbar

Topcoat toolbar