Fixed|UI|Client: Crash in the VR settings dialog

The "Apply Desktop Settings" button was not being created.
Oculus Rift|UI: Added slider for configuring pixel density

Allows for a quality/performance tradeoff.
Renderer|VR: Apply actual head position when clipping etc.

Todo: Need to use the eye offset, too.
Renderer|VR: Eye offset applied to the eye origin (for clipping etc.)

Also refactored the model view matrix function to be somewhat clearer.
Menu|All Games: Added "Reset Tracking" in the Controls menu
Oculus Rift|Renderer: Prevent cheating by peeking through surfaces

In Oculus Rift (head tracked) mode, putting one's head physically
through walls and planes results in a black screen.

Todo for later: The blanking out should occur at near clip distance.
Fixed|libappfw|Oculus Rift: Build error when not using LibOVR
libcore|Package: Package info file can also be named "Info.dei"

"Info.dei" takes precedence over "Info"; if both found, only "Info.dei"
is read.
Windows|libappfw|Fixed: Build error in OculusRift
Merge branch 'master' into common-episode-definition