motu: add framework to support mark3 mixer GUI interfaces within ffado-mixer.

git-svn-id: http://subversion.ffado.org/ffado/trunk/libffado@2418 2be59082-3212-0410-8809-b0798e1608f0
Merge branch 'master' into motu-mk3-mixdsp

Conflicts:
	configuration
	support/mixer-qt4/ffado/panelmanager.py
Merge branch 'motu-mk3-mixdsp' of github.com:kmixflow/ffado into motu-mk3-mixdsp