* Augment raymath.h with useful functions

* Rename Vector2ClampMagnitude and Vector3ClampMagnitude to Vector2ClampValue and Vector3ClampValue

* Remove Vector3{Up,Down,Left,Right,Forward,Backward}

* Fixed functions Vector2Angle and Vector3Angle

* typo

* Unrolled everything.

Following the pattern in Vector3Normalize.

functions use radians, making this awkward to use.

CONVENTIONS:
  - Functions are always self-contained, no function use another raymath function inside, required code is directly re-implemented inside
  - Functions input parameters are always received by value
  - Functions use always a "result" variable for return
  - Functions are always defined inline
  - Angles are always in radians (DEG2RAD/RAD2DEG macros provided for convenience)

Replaced: Returns -> Get