Fix issues with particles, colors can now be interpolated
Close #135 refactor SceneNode to Scene
Close #76 Implement timer api
Merge branch 'master' of github.com:eonarheim/Excalibur into dev-erik
Merge branch 'master' of github.com:eonarheim/Excalibur into dev-erik
Fix test run on gruntfile
Close #137 Game.extend now supported
Break particles into a separate file
Close #91 Implement triggers
Merge changes from master
Merge pull request #142 from eonarheim/dev-erik

Merge fixes to particles, timer api, fixes in grunt file, and triggers