_StoreMixin: refactor collection cleanup out of _setCollection into _cleanupCollection
_StoreMixin: Reset row variable between distinct observable events
DnD.html: Switch before to beforeId
Fix #874: tree: Remove unnecessary code causing nested expansion issues
tree: Add enableTransitions column definition property
Merge branch 'master' into dev-0.4
Tree: Remove unnecessary code causing nested expansion issues

(Ported from 0.3)
Remove util/mouse module and update tests
Update mouse module documentation

Includes update to CHANGES.md noting util/mouse removal

Also includes code reformatting in test/Grid_mouseevents.html
Tree doc updates RE enableTreeTransitions
Update demos for 0.4
Further demo cleanup for 0.4

dTuned:

* Refactor data.js to data.json + RequestMemory
* Re-flow as necessary to accommodate initial async query
* Rename variables to make more sense
* Make field names lowercase
* Reformat according to new style guide

multiview:

* Separate store data to its own JSON resource and use RequestMemory
* Use dojo/on for event handler registration
* Reformat according to new style guide

todo:

* Remove a couple of superfluous statements/properties
* Reformat according to new style guide
demos: Use require.toUrl for portability regardless of page location
DnD: Fix issue when dragging previously-dragged row to end of grid
DnD: Prevent error in short-circuit logic on long drags

This specifically involves cases where an item is dragged a long enough
distance such that the original row is destroyed.
DnD: Cleanup

I'm a horrible person.
Merge branch 'master' into dev-0.4

Conflicts:
	extensions/DnD.js
Merged to latest dgrid