intial implementation of markers
add marker events
Switched the build process to use Polymer UI

The deployed Polymerized output loads, but looks very garbled, and some functionality isn't accessible because of that (non-system dialogs are outside the window, for example).
Moved spark_polymer_ui.* to the top level dir

This resolves 3 problems with the deployed code (`grind deploy`) at once:
1) Fixes the bad output paths for the Open File and New File buttons (relative original paths were resolved to be under lib/polymer_ui).
2) Eliminates the necessity to include widget.dart as a file path, not 'package:...', in spark_polymer_ui.dart (this doesn't fix the original bug #500, however).
3) Eliminates the "../../" prefix in all widget package imports in spark_polymer_ui.html, and correspondingly the necessity to massage this file in grind.dart during deployment.
Bump the app's version due to swithover to the Polymer UI
Merge branch 'master' into work
Addressed review comments + reverted some overlooked wrong changes
Addressed review comments #2
Addressed review comments #3
added tests
Merge branch 'master' into work
fix nits
Merge branch 'upstream/master'
addressed comments
Fixed some missing outputs in deployed code
Minor naming fix in library names.
Merge branch 'dev' of http://github.com/camfitz/spark into dev
Merge pull request #563 from camfitz/dev

Fixed library names of git commands.
Replaced 'compile' with 'deploy' in all build sequences

This finalizes replacing non-Polymer with Polymer in the build toolchain. For example, 'archive' now creates a zip of the deployed Polymer UI.
Merge pull request #561 from dart-lang/markers

Add makers to workspace