* Tweaked flycam a bit too, but not much.
* Refactored the API/C# side camera classes to avoid exposing a ton of
stuff just to do relative rotations in the arcball via quaternions.
* The arcball lookat position can also be dragged with alt-click or
middle click.
* Also supports other elements as position not just magically-selected
"POSITION" element.
* Note at the time of committing there are still some warnings in MS
headers that you might need to suppress in a couple of files.
* 3rd party code just has the warnings suppressed for ease of merging.
* The majority of warning fixes were for local variables shadowing
other locals, function parameters, or members. In most cases they
weren't a problem, but in some cases it was potentially dangerous!
* Since we decode the visual colours into an integer by looking them up
in the overdraw ramp rather than re-running to get an integer return,
we make some invisibly subtly different colours above the highest
overdraw colour, and use these to tell overdraw levels above 20.
* ie. not just an unnormalised mantissa plus biased exponent, it has proper
IEEE style float properties with hidden bit on the mantissa etc. So full
decoding is necessary, contrary to what some of the docs say :(.
* http://blog.selfshadow.com/2012/11/12/counting-quads/
* Quad Overdraw based on ScenePS4 from the revised implementation. The
colours are new, up to 20 levels. Picking pixels shows the overdraw level
* Available per-pass and per-drawcall, a pass defined the same way as in
the mesh view, drawcalls since last clear or RT change.
* List of events now passed through to RenderOverlay the same as RenderMesh