3DMouse working on Windows and Ubuntu

Implementation of 6DOF 3DMouse input (Windows only). Not tested yet.

Put libraries into one libs directory under qgroundcontrol. Changed the neccessary files with references to those libraries.

Fixed imagery rendering issues. Robot position in Pixhawk3DWidget is now derived from the global pose (lat/lon/alt) instead of the local pose.

Added visualization of point cloud data from Kinect camera. Colorized point cloud visualization to follow soon.

corrected a compile warning in Wayppoint.cc, made adaptions to Freenect for the current revision of the code (update libfreenect repository!), commented out pixhawk poi mavlink code - needs fixing

Changed status message in qgroundcontrol.pro, fixed compile error in class Freenect (void* did not work)

Switched from flite for speech on the Mac to built-in MacOSX speech synthesizer. Fixed build system for 64-bit builds (using official SDL.framework, and Qt frameworks).