Allow addons to have public trees.

* Public is namespaced by default under the addons package name.
* Add simple easy to override method lookup pattern for customizing
  treeFor on a type by type basis.
Merge pull request #1930 from rwjblue/addon-public-tree

Allow addons to have public trees.
Ensure startApp helper users correct application params.
Merge pull request #1943 from rwjblue/ensure-start-app-uses-correct-params

Ensure startApp helper users correct application params.
Updates broccoli-asset-rev to 0.1.1
Merge pull request #1945 from rickharrison/update-asset-rev

Updates broccoli-asset-rev to 0.1.1
Add empty function when resource is singular.
Merge pull request #1946 from abuiles/generators-enhancement

Add empty function when resource is singular.
Update app blueprint's package.json/bower.json to depend on ember-data directly
Remove duplicate package.
Merge pull request #1951 from rwjblue/update-package-deps

Remove duplicate package.
Limit concurrent number of copy operations.

If the output directory contains more than 16 files (for example if you
have merged in some fonts/themes/etc) you would get EMFILE errors due to
the copy operation.  This limits the concurrency when copying to 2.
Merge pull request #1873 from jayphelps/patch-2

Update app blueprint's package.json/bower.sjon to depend on ember-data directly
Merge pull request #1952 from rwjblue/limit-concurrent-operations

Limit concurrent number of copy operations.
Allow array of paths to the preprocessCss phase

- Ensure backwards compat for app.scss -> <app name>.css
Use project.options.outputPaths hash for dest. files