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
Update bundled npm version.
Ensure regression does not happen
Merge pull request #2199 from bcardarella/bc-addon-blueprint-package-fixes

Ensure regression does not happen
Update broccoli-file-remover to 0.3.1.

This version fixes failures on Windows.
Merge pull request #2204 from rwjblue/update-file-remover

Update broccoli-file-remover to 0.3.1.
Ensure bower.json gets correct metadata

It is debateable if the `name` property is even necessary, but in any
case it definitely shouldn't render as `dummy`.
Merge pull request #2202 from bcardarella/bc-more-meta-data-test

Ensure bower.json gets correct metadata
Merge pull request #2198 from rwjblue/update-vendored-npm

Update bundled npm version.
Update version.
Remove less from initial registry.

Now it should be pulled in from ember-cli-less.
Merge pull request #2210 from rwjblue/remove-less

Remove less from initial registry.
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