merged from lp:mixxx
added gain knob and a basic LED mapping
store pointer to creating CO in CDP
Removed separate Hash table from ControlObject.
Merge branch 'master' into atomic-co2
Introduce QSharedPointer for ControlDoublePrivate
Fix double add to hashtable
Delete all leaking cdp one shutdown
Changed some ControlObjectThreadMain instances to ControlObjectThread if
no direct connection is used.
Changed some more ControlObjectThreadMain instances to
ControlObjectThread if no direct connection is used.
Delete leaking controls
Changed control delete order for modified files to reverse of construction order (following google style guidelines).
Finaly Changed remaining ControlObjectThreadMain instances to
ControlObjectThread where no direct connection is used.
Merge branch 'master' into atomic-co2

Conflicts:
	src/control/control.cpp
	src/control/control.h
Merge branch 'master' into atomic-co3
Moved recording status calls to a member variable for thread safety.
Typos and formatting.
Added DS_Store to gitignore
Merge branch 'delete_leaking_controls' into recording_improvements
Merge branch 'recording_improvements' of https://github.com/cpill0789/mixxx into recording_improvements