sin(), cos() functions cached and replaced by float c99 versions sinf(),
cos()

...and improved mouse gestures support
Some testing still required...

Required by ProcessGestureEvent()

Mouse input is interpreted as touches to allow mouse gestures
detection... and get an unified inputs system for all platforms!

- Fixed gestures hold detection.
- Improved hold state detection for little touch position increments
(sensitivity).

Removed GLEW external dependency, now it works with GLAD
Kept GLEW path, just in case... detected weird behaviour when testing
with gDEBugger

This reverts commit 423a45ac85.

Added support for single header implementation and also inline functions
support

- Added simple ray-sphere collision detection.
- Added extra function with extended parameters to obtain collision
point vector.
- Fixed bounding box calculations init values (were causing compiling
errors).

look over for errors

Reviewed vertex type variables

- Added function WorldToScreen(...).
- Added world to screen example.
- Review GetMouseRay() comment.
- Removed deprecated lighting functions from raylib header.