Add internal documentation building via YUIDoc

Run `npm run docs`

Taken directly from Ember.js with minor changes, with exception that
generator will also create HTML docs as well as JSON data. We can fall
back on this until the ember-cli.com site includes this API
documentation.
Add doc signatures for EmberApp

Extremely minimal doc comment blocks. Not yet qualified to complete.
Add documentation about documentation
Mention the possibility of top-level errors until testem reports this
Merge pull request #2216 from joostdevries/improve-error-message-notests

Mention the possibility of top-level errors until testem reports this
Give clear error when failing to read config from meta
Allow filtering tests run through testem.

Adds `--filter` command line option to `ember test` and `ember test
--server`. The `filter` parameter is used by QUnit to filter based on
module name and test description.
Merge pull request #2223 from linstula/allow-filtering-tests

Allow filtering tests run through testem.
Merge pull request #2219 from joostdevries/error-if-config-meta-missing

Give clear error when failing to read config from meta
update broccoli
Merge pull request #2224 from csantero/update-broccoli

update broccoli
Allow addons to inject middleware into testem

This PR depends upon https://github.com/airportyh/testem/pull/410 being
accepted

Primarily the use case is with any addon that injects a middleware into
the ember server's, this will allow addon authors to also expose that
middleware through `ember test` if/when noted PR above is accepted by
@airportyh
Merge pull request #2128 from bcardarella/bc-support-testem-middleware

Allow addons to inject middleware into testem
Fix description for service-test
Merge pull request #2235 from jonnii/bug/spelling-error

Fix description for service-test
Add a few more content-for placeholders.

* Add `{{content-for 'body'}}` to `app/index.html` and
  `tests/index.html`
* Add `{{content-for 'test-head'}}` to `tests/index.html`
* Add `{{content-for 'test-body'}}` to `tests/index.html`
Merge pull request #2236 from rwjblue/content-for-sprinkles

Add a few more content-for placeholders.
if the error has an error.file, display it.
Merge pull request #2237 from stefanpenner/error-file

if the error has an error.file, display it.
Refactor: Add Multiple bower packages in one statement

Remove unnecessary semicolon

Add tests for addBowerPackagesToProject

Properly test addBowerPackageToProject