Add menu item that toggles VR display mode

Toggles the display mode if a Rift is found connected at program start.
Experimenting with ambidextrous sixense mouse input
Invert hydra move view and thrust controllers to match consoles
Merge branch 'master' of https://github.com/highfidelity/hifi
Store the last mouse move input type for application overlay
Support for multiple oculus overlay magnifiers
Removed left handed menu option
fix reference to attribute in STUN packet
Merge pull request #3017 from birarda/master

fix offset to attribute in STUN packet
Made applicationoverlay more readable
Fix for click and drag with sixense
Merge branch 'master' of https://github.com/highfidelity/hifi
Removed some unused variables.
let QUrl do its automatic percent encoding for address lookup
Merge pull request #3018 from Barnold1953/master

Ambidextrous sixense mouse usage
Fixed command line args parsing bug
Updated AssignmentClient to use HifiConfigVariantMap...
...and also updated DomainServer to appropriately use boolean options
Merge branch 'master' of git://github.com/highfidelity/hifi
added space between expressions in ternary operator
Merge pull request #3021 from jmgrosen/19778

Code Review for Job #19778