Mixer: Avoid unecessary redraws (hidden widgets, when mixer strips are added). Also, draw fonts of inactive widgets in dimmed color.

Conflicts:
	mixer/src/Mixer.C
Timeline/Control_Point: Don't draw with zero width.
NSM: Don't wait on clients that have died while executing a command.
FL/Fl_Scalepack: Fix resize bug.
Mixer: Implement two way mapping for OSC learning.
OSC: Simplify OSC signal protocol.  Add midi<->osc gateway program.
Mixer: Use a four color gradient for meters.
Mixer: Add connection/disconnection submenu to controller module context menu.
Mixer: Improve appearance of panner/spatialization widget with pixmap background.
Mixer: Tweaks to by-number learning.
Mixer: Avoid unecessary redraws (hidden widgets, when mixer strips are added). Also, draw fonts of inactive widgets in dimmed color.
Mixer: Implement Spatialization Console.
Mixer: Remove dead signal feedback code.
Timeline: Mark ports as Terminal.
Mixer: Clip children when drawing modules.
nonlib: Fix bugs in JACK::Port.
Mixer: Implement Spatializer module.
OSC Signal cleanups.
Mixer: Fix initial size.
Update NTK.