Add smw.util.async

* Add smw.util.async.load()
* Add smw.util.async.isEnabled()
* Add smw.debug()
* Renamed capitalize() to ucFirst()
* Fix jsDuck docs

## Example
var fn = function( options ) {}

smw.util.async.load( $( this ), fn, { 'id': ... } );

Change-Id: Idfd34c7f29a8f112f116d9080ca9991ffcfa77a3