Using normalized [0..1] input points

A deeper revision required, not clear enough for the user
Key: Create a PhysicObjects pool

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.