No model available, this example should probably be redesigned...

Oculus API has changed so much that it has no sense to keep this example here... it was funny to test it in the past...

- Renamed Begin3dMode() --> BeginMode3D()
- Renamed Begin2dMode() --> BeginMode2D()
- Renamed End3dMode() --> EndMode3D()
- Renamed End2dMode() --> EndMode2D()

They were disabled because they failed to build,
but this patch set fixes the build on Linux and macOS.

This doesn't apply to the AppVeyor build on Windows yet;
it currently fails at linking with OpenAL.

- Removed raylib_demo (outdated)
- Removed some old examples

- Removed rbmf font example
- Reviewed physac examples