Accordion improvements:
- Accepts dynamically added accordion items (we use .on on parent instead of attaching directly to existing items)
- Returns a usable accordion JS object (a bug prevented this earlier)
- Provides utility functions to open/close and recalculate the height of specific accordion items
- Provides an attachable callback for the open/close methods, which is executed at the end of the open/close animation
Bumped up the patch version number
- Created settings for default classes
- Created hooks into open/close/all transitions via API, and removed the callbacks from open/close API
- Switched to pure API call format (.open) instead of previous string argument format (.accordion('destroy'))
- Updated documentation to present new features
Updating package version to 0.3.0-pre.

* Incrementing to 0.3.0 as this is an API level change.
Fix usage of this which isn't correct given the context

* the function is called from.
Merge pull request #3 from mobify/accordion-improvements

Accordion improvements: