Crash on shutdown. Uninitialized pointers leading to spurious operations.

[Craniac]

ofxKinectCommonBridge::stop() checks mapper against NULL before dereferencing it, but (at least for a debug build), the value was not initialized, with the system setting it to 0xcdcdcdcd or somesuch, instead of NULL. Probably should be initialized in the constructor, along with nuiSensor and irPixelByteArray.