FilesController: switch to posting events to EventBus rather than calling delegate's API

This will be used in SparkPolymerUI to adjust the UI based on what it selected (e.g. disable Push To Chrome Web Store for non-Chrome apps).
EventBus: tighter type/data integration + clearer event hierarchy + easier onEvent() usage
upgrade to polymer 0.10.0-pre.9
Naming + comments
Merge remote-tracking branch 'upstream/master' into switch-file-controller-to-event-bus
Review comments
Review comments
Merge pull request #1638 from ussuri/more-work-on-event-bus

More work on event bus
Merge remote-tracking branch 'upstream/master' into switch-file-controller-to-event-bus

Conflicts:
	ide/app/lib/editors.dart
	ide/app/test/event_bus_test.dart
Implemented new search behavior (fixed #1549)
Manual merge with EventBus changes
Naming + new predefined BusEvent's for errors and progress messages
Merge pull request #1640 from ussuri/more-work-on-event-bus

Naming + new predefined BusEvent's for errors and progress messages
Merge remote-tracking branch 'upstream/master' into switch-file-controller-to-event-bus

Conflicts:
	ide/app/lib/event_bus.dart
Renaming
Merge pull request #1641 from ussuri/switch-file-controller-to-event-bus

Switch FilesController over from dedicated delegate to EventBus for notifying listeners
Merge pull request #1637 from jmesserly/polymer_pre9

upgrade to polymer 0.10.0-pre.9
Fixes and nits
Merged
re-work the dartium bootstrap sequence