To be more generic and configurable

Variable t was read and modified without interleaving sequence points,
technically undefined behavior. Report by Clang's -Wunsequenced

It should be reviewed more carefully...

Requires some work, distortion shader could be move out of raylib to
example code...

Added: DrawRectangleGradientV()
Added: DrawRectangleGradientH()

Increment raylib version and so lib version number.

to emulate OpenGL funcionality

SetWindowTitle()
GetExtension()

Moved function DrawRectangleT() from text module to shapes
Added some comments

Some people might find this handly

On DDS files mipmapCount header parameter could be unused and set to 0,
resulting in a wrong mipmap count and wrong compressed texture loading.

Usefult to draw rectangles using default font texture

Physac wasn't working on OS X.  It looks like the necessary timing code wasn't being compiled in by the preprocessor.

fixes #340

To multiply Vector3 by Vector3

For consistency!