Partially create and use an Interaction class
Move inertia related things into Interaction
Move activeDrops into Interaction
Pointer event listeners to Interaction prototype
Move more things into Interaction
Move more things into Interaction
Move a lot more things into Interaction
Fix tap events
Add element property to Interaction objects
Fix and improve PointerEvent support
Improve getInteractionFromEvent
Merge branch 'master' into multiple-interactions

Conflicts:
	interact.js
Add interaction argument to InteractEvent
Record pointers and get Interactions more smartly
Modify dropzone demo for multiple interacitons
Use interaction.pointerMoves[0] to get event XY
End interactions correctly on blur
Get eventXY correctly for inertia events
Do not allow multiple interactions on an element
Reduce use of getInteractionFromEvent for coords