OpenNI2-FreenectDriver: Move static and global symbols into Utility.hpp
OpenNI2-FreenectDriver: Print libfreenect version when driver is loaded
OpenNI2-FreenectDriver: Use explicitly-sized integers for buffers
OpenNI2-FreenectDriver: 0-initialize structs

Signed-off-by: Benn Snyder <benn.snyder@gmail.com>