Add toggle for user interface display

- "/" toggles UI (incl. stats if displayed); menu View > User Interface
- "%" = toggle status; menu View > Stats
- Acts on normal, 3DTV, and Oculus display.
Fixed performance timer scope
Resize the overlay framebuffer when the application window is resized
adding "export QT_CMAKE_PREFIX_PATH=/usr/local/opt/qt5/lib/cmake" for qt5.2.1
adding "export QT_CMAKE_PREFIX_PATH=/usr/local/Cellar/qt5/5.2.1/lib/cmake" for qt5.2.1
Another improvement to clapping to match animation pace with keystrokes
Fix script errors not being reported

Script.update event needs to be emitted after reporting any script errors.
Merge pull request #3140 from ctrlaltdavid/script_error_reporting

Fix script errors not being reported
Merge branch 'master' of https://github.com/worklist/hifi
switched to better sounds for clapping
Guard _framebufferObject deletion
Integrate UI toggling menu item and Hydra UI toggling

They work together and both fade the UI in / out.
Merge pull request #3142 from mpursley/master

adding "export QT_CMAKE_PREFIX_PATH=/usr/local/Cellar/qt5/5.2.1/lib/cmake" for qt5.2.1
Merge pull request #3141 from ey6es/metavoxels

Fixes, congestion control for metavoxel streaming.
Merge pull request #3139 from PhilipRosedale/master

Another improvement to clapping to match animation pace with keystrokes
Hand low velocity filter as a menu option
removed some debug logs
Merge pull request #3138 from ctrlaltdavid/19836

Code Review for Job #19836
Merge pull request #3143 from PhilipRosedale/master

Add Low Velocity Filter for hand movement as menu option
Very basic metavoxel save/load.