Add LLMotionController* LLMotion::mMotionController

This is needed for synchronization: motions will have to start
(with a specific start time offset) from a point in the code where
only the motion object is available.

I added/used LLMotionController& in a previous commit, this was
now changed into a pointer. There is (obviously) not much reason
for that, but also no disadvantage: the diff relative to LLs code
doesn't get larger since the references where already added, too.

Conflicts:
	indra/llcharacter/llkeyframemotion.cpp
	indra/llcharacter/llkeyframemotion.h

indra/llcharacter/lleditingmotion.cpp

@@ -49,7 +49,7 @@ S32 LLEditingMotion::sHandPosePriority = 3;
 // LLEditingMotion()
 // Class Constructor
 //-----------------------------------------------------------------------------
-LLEditingMotion::LLEditingMotion(LLUUID const& id, LLMotionController& controller) : AIMaskedMotion(id, controller, ANIM_AGENT_EDITING)
+LLEditingMotion::LLEditingMotion(LLUUID const& id, LLMotionController* controller) : AIMaskedMotion(id, controller, ANIM_AGENT_EDITING)
 {
 	mCharacter = NULL;