add dev server to grunt
move async GA code to <head>
consistency in watch tasks
refactor playground code
update documentation to cover:

* angular directive
* auto-merge of options
* callbacks
add changelog
CSS cleanup
cache bust assets
small markup tweaks
vendors scripts can be included in any order
dev setup is now default grunt task
styling tweaks

* simplify feature header
* remove unnecessary styles
* introduce island object, used for forms and button groups
update changelog
improve page titles
describe browser APIs headroom is dependent on
improve description of how to use library plugins
final docs for v0.4.0
add thanks to changelog
Better explanation of browser support