Trying to resolve failed initial load of post listing

- Tidy up binding of collection events in PostListView
- Remove extra call to next/prev pagination helpers in pagination
partial
- Whitespace clean ups
Map View - fix error check transitions in Chrome

Check e.originalEvent.target AND e.originalEvent.originalTarget since
chrome and firefox differ on this.
Posts API: Delete any missing attribute values

If a post is updated and the data is missing previous values, remove
these
values from the DB.
Handle forms with multi-value attributes in UI

Add backbone forms List editor, use this for forums with cardinality >
1.

Remove backbone deepmodel and manually handle parsing values object
into values.xyz. Deep model was causing havoc with backbone validation.
This way we have control over the handling.

Add a custom validator 'validateArray' to handle validation of the
multi value fields
Move backbone forms loading & extension into seperate module

Moving backbone forms loading into forms/UshahidiForms module.
Move the List Object hack out of EditPostView.
Move the validateArray custom validator into UshahidiForms too.