Update status for folders.
Merge pull request #2228 from dart-lang/update_folder_status

Update status for folders.
Merge branch 'master' into fix_update_index
Merge pull request #2222 from dart-lang/optimize_commit

Optimize commit
Minor fix in SparkFlags
Merge pull request #2232 from ussuri/small-fixes-2

Minor fix in SparkFlags
Fix path for Polymer core-elements dependency
Fix order of Future handlers: could prevent Bower error from being displayed
Dev flags: merge maps with same name defined in different config files instead of overwriting

This will be used shortly for advanced configuring of Bower.

E.g.
app.json:
  "some-map": {
    "a": "aa"
  }

.spark.json:
  "some-map": {
    "b": "bb"
  }

will result in:

  "some-map": {
    "a": "aa",
    "b": "bb"
  }
Merge pull request #2233 from ussuri/improve-dev-flag-parsing

Dev flags: merge maps with same name defined in different config files instead of overwriting
Merge remote-tracking branch 'upstream/master' into refine-polymer-project-templates
Merge remote-tracking branch 'upstream/master' into refine-polymer-project-templates
Add exceptions to git branch.
cleanup exceptions in checkout.
Refactor git/exception.dart.
Better exception throwing in git fetch.
Better exceptions in index.dart.
more exception handling.
Add exceptions in objectstore.
Fix an error: prevented code from doing what was intended