Handful of fixes and update for LibOVR 0.2.4

This fix adds a few fixes related to view angles not being set right during intermissions/when resetting HMD orientation and prevents magnetic auto-calibration from trampling any user configured calibration (added in LibOVR 0.2.4). It also adds the ability to specify the size of the crosshair/laser to help mitigate some of the visibility problems when it is viewed underwater - the blending makes it really hard to see (or disappear entirely) at smaller sizes.

I typo'd my one of my commit messages, the new function is VR_SetAngles() - whoops.