UI|Stereo 3D: Added a VR settings dialog

Todo: Add all the VR settings.
Stereo 3D|UI: Added settings to the “3D & VR Settings” dialog

Also, updated some Oculus Rift defaults according to averages
from Wikipedia (average male IPD, height).
Fixed|UI|Client: Relocate popups when UI composition mode changes

If the compositor is activated, open popups must be relocated to
the compositor instead of staying in the root widget.
UI|Stereo 3D: Show latency setting only when head tracking available
Input|Bindings: Only active input devices should be considered

When checking for existing bindings for a control, only active input
devices should be taken into account.
Stereo 3D|UI: Oculus Rift settings only appear when Rift connected

Also added a quick-setup button for setting a good configuration for
the Rift.