Custom events implementation

[jharding]

See #68. Still WIP.

[jharding]

No longer a WIP, I've finished implementing the batch of custom events for v0.9.0.

[jharding]

Should the triggering of typeahead:initialized be deferred?

$('.typeahead')
.on('typeahead:initialized', function() { alert('called'); })
.typeahead({ /* ... */)
.on('typeahead:initialized', function() { alert('never called!'); });