Add touchpad delegate to pass touch events

I need to bubble the touch events up to the view
controller so they can, eventually, be converted
into OSC messages.

I also added a property to the view controller to
keep track of the selected channel so that this
can be passed in the OSC message.
Add OSC message sending using CocoaOSC

The project now expects to be run in a workspace
along side the CocoaOSC project.

I was running into errors unless I added a local
copy of NS+OSCAdditions (which I copied from the
CocoaOSC source and edited to remove retains and
releases)