Better error messages
Merge pull request #2043 from ef4/error-messages

Better error messages
Allow addon/ to contain any known JS filetypes.

This allows usage of `*.coffee` (or any other `js` type preprocessor).
Ensure window.EmberENV uses the EmberENV key from config/environment.js.
Merge pull request #2054 from rwjblue/allow-addons-to-handle-all-types

Allow addon/ to contain any known JS filetypes.
Merge pull request #2057 from rwjblue/use-ember-env-properly

Ensure window.EmberENV uses the EmberENV key from config/environment.js.
Do not use inline script tags.
Merge pull request #2058 from rwjblue/csp

Do not use inline script tags.
Add description for generated blueprints
Merge pull request #2062 from kamalaknn/desc-for-blueprints

Add description for generated blueprints