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
try clearing npm cache on appveyor build
this shouldn't work
more bad ideas
node on windows should be outlawed
Merge pull request #2106 from hparra/feature-add-yuidoc-building

Add yuidoc building
Tweak helper blueprint

Fixes #2228
Merge pull request #2257 from jgwhite/tweak-controller-blueprint

Tweak helper blueprint
Streamline initializer and service blueprints

Fixes #2259
Merge pull request #2260 from jgwhite/streamline-exports

Streamline initializer and service blueprints
Log proxy request when using http-proxy.
Fixing a typo, exists -> exits, within serve.js
Add ember-export-application-global to default app blueprint.
Merge pull request #2270 from rwjblue/export-global

Add ember-export-application-global to default app blueprint.
correct typo
Merge pull request #2274 from dondanhill/master

correct typo
Fix gitignore in app blueprint

Directory patterns should not end in `\*`.
Merge pull request #2285 from xymbol/fix-gitignore

Fix gitignore in app blueprint