Better console logs for some errors:
- Improved error reporting for swallowed exceptions in ProjectModel, AppInit,
FileTreeView (show stack and actual exception message)
- Clearer error message when extensions fail to load due to requiring a
non-existent module

Additional small cleanups:
- Fix ThemeSettings dropdown change listener so it is properly specific
- Docs improvements for tree & working set decorators
- Several other docs tweaks
Merge remote-tracking branch 'origin/master' into pflynn/improved-error-logs

* origin/master: (69 commits)
  Issue #2281, display project name in window title
  Remove the negative margin hack which is no longer needed
  Updated by ALF automation.
  Disable Mac-specific `backface-visibility` rules that cause Windows text rendering (on newer Chromiums) to strop doing subpixel antialiasing (aka ClearType) anywhere in the UI.
  Updated by ALF automation.
  JSDoc
  strip dirty dot from file name
  fix style sheet parsing
  remove unused var
  remove unnecessary call to EditorManager.getFocusedEditor()
  Updated by ALF automation.
  Validate maxResults is an integer
  ValidationUtils improvements
  Add new pref maxCodeHints
  Nits and doc.
  Use this.name for toString() instead of this.id.
  * Mark DocumentManager's old events as deprecated *before* extensions have a chance to register for them. Clean up docs. * Fix $() shim warning: it was incorrectly flagging r.js-concatenated extensions as core code, since the whole path prefix is wiped off in that case. Unfortunately the same is true of core code in production builds, making the two indistinguishable. So: only flag as core code when the path indicates a dev build
  Updated by ALF automation.
  Fix bug with detaching one() listeners via off(), spotted thanks to a question from @Mark-Simulacrum. With unit tests.
  - Convert PreferencesSystem & PrefixedPreferencesSystem to use EventDispatcher, while preserving their existing public API with nonstandard on()/off() APIs - Remove long-deprecated ability to create resizable bottom panels via makeResizable() without using createBottomPanel(). (Simplifies code a bit, but leave in a console error log in case anyone hits this in the future). - Fix Editor docs about keyboard events - Docs & error message tweaks from code review - Simplify assert() calls that are meant to force a debugger pause
  ...

Conflicts:
	src/utils/AppInit.js
Code review: Further improve docs for icon/CSS providers in working set &
file tree. And...
- Fix FileTreeView so tree icon provider can return undefined without crash
- Update docs to reflect that tree CSS provider really can return undefined
- Remove copied/redundant docs in FileTree View
Merge pull request #9901 from adobe/pflynn/improved-error-logs

Better console logs for some errors, plus small other fixes