GLMixer Code

BugFix Source Edit replacement (recreate source option)

Implemented OSC properties for changing begin, end and timing of video.

OSC Broadcast of the information for connecting to GLMixer on start of
OSC server. Additional property for timing of a media file.

Added OSC properties to control playing of media source and videofile.

Updated the names of presets in MixingToolbox to avoid spaces so they
are compatible with OSC messages.

Added the OSC 'preset' attribute to sources : applies a preset from the
Mixing Toolbox from OSC.

Compilation fix for old G++ (before C++11).

Added OSC target 'select' to select the current source from OSC using
'next' and 'previous' attributes. Controlling the current source is then
operated using the 'current' target.

New OSC: Broadcast of message in reply to OSC request. Implemented
request for name of source and count of sources. Improved implementation
of OSC message handler.

Cosmetics GUI and code.