Merge branch 'master' of https://github.com/worklist/hifi into recursive_voxel_delete
Merge branch 'master' of https://github.com/worklist/hifi into gyroquat
Use quaternions for rotation estimates.
Enhanced workiness.
Acceleration is presumably relative to the current orientation.
Add back yaw decay the quaternion way.
Coordinate fix.
More compiley.
Approach the "down" direction more rapidly.
Merge branch 'master' of https://github.com/worklist/hifi into gyroquat
repair indentation and NULL comparisons in Avatar class
Merge pull request #499 from ey6es/gyroquat

Converted gyro rotation computations to use quaternions, fixed coordinates and increased rate of convergence to current gravity.
Removed double negation for coordinates, world aligned orientation -> camera
orientation, removed roll.
Added debug->run timing tests option to speed test some common functions  (please add some more, bottom of util.cpp
Add pitch/yaw scale preference to control degree of view rotation.
Think this needs to be a double.
OK, one more try.
One more "one more try."
We need to sync in order to ensure that the settings are saved.
#19365 - Frustum menu moved inside the Debug menu