Rename 'yeoman' var to 'config'

Closes #285
Merge pull request #287 from creynders/patch-2

Rename 'yeoman' var to 'config'
Bower supports Github shorthands
Rev the favicon and touch icons if they are referenced in index.html

Note that this *breaks* automatic references to the favicon and apple touch
icons. Icons must be referenced in index.html.
Added images folder to assetsDirs - usemin
Used the wrong variable yeoman instead of config
Merge pull request #264 from robwierzbowski/rw/rev-favicon

Revv the favicon
Merge pull request #290 from kartikluke/master

Added images folder to assetsDirs - usemin
Changed notation for usemin
Merge pull request #292 from kartikluke/master

Changed notation for usemin