Interact Nodes: BUG FIX: Leap Cursor pointer-up,moved,down events

LeapCursor was not producing the aforementioned events due to an error
in the code (A comparison was being made between a function and a value
when the comparison should have been with the result of applying the
function to a value)
Interact Nodes: Drawing Wires!

WORD OF WARNING: Holding positions of nodes/ports/wires that will change
is a *bad* idea. Better to define functions that provide you with direct
access to the position property of the paperjs Item.

 * BUGFIX: hit testing was sometimes confused by the cursor icons (as
   appear above everything else). Disambiguating by only hit testing on
   the view-layer now.
 * BUGFIX: Forgot to pass wire to rem-output instead of node (as part of
   making register-output symmetric)
 * Preventing self loops when drawing wires, as they are impossible to
   remove if they occur.
 * Removing redundant Node.sending-wires list (the Node.send-list
   variable now serves that purpose).
Interact Nodes: Removing dummy data