* Unify FPS and V-Sync controls and behavior (#181)

- DirectX's "Match Refresh Rate" is now a checkbox like in OpenGL and Metal.
- Clamp max FPS to refresh rate when V-Sync is enabled or can't be disabled, regardless of the FPS sliders setting, to avoid slowdown in Metal / OpenGL and dropping frames in DirectX as much as possible.
-FPS slider allows up to 360 FPS in every renderer.
- More descriptive V-Sync tooltip

Also fixes GetInterpolationFPS() not being used to calculate desired FPS.

* "Jitter Fix" to "Render parallelization" checkbox

Changes the Jitter Fix FPS threshold slider to a simple checkbox named "Render parallelization".
CVar also changed to "gRenderParallelization".

* Fix V-Sync checkbox not representing the default