Integrated Error Console with Apps DevTool

This integrates the ErrorConsole with the Apps Developer Tool.
Chrome changes which would accompany this change are here:
https://chromiumcodereview.appspot.com/131973019/

This is still in-progress, but is the gist of the work.  Please let me know what you think, and if there's anywhere I should be taking a different approach.

I'll add some screenshots of the differences next week when I'm back at my workstation (Chrome Remote Desktop doesn't quite have enough power).

Cheers,
  Devlin