Add git objectstore.

Also adds utility class file_operations.
Remove extra whitespaces.
Moved the entire implementation under ide/, further to be split into ide and ui_lib.
Factored out the beginnings of Polymer-based UI library from ide/app/polymer into widgets/.
Addressed comments: library name + description in .yaml
Addressed comments: moved AUTHORS etc. around, added README.md where approptiate.
Fixed comments by Devon.
Merge branch 'master' of https://github.com/dart-lang/spark into object_store
return fix.
Merge pull request #75 from dart-lang/object_store

Object store
added the ability to test the chrome+dart2js version of the app (as well as the dartium version)
style nit
Add git objectstore.

Also adds utility class file_operations.
Remove extra whitespaces.
added --chrome-stable and --chrome-dev flags
upgrade ace
ws change in logging output for test runner
Fixed comments by Devon.
return fix.
Moved the entire implementation under ide/, further to be split into ide and ui_lib.