New implementation allow enabling additional textures per batch only.

Reduce size and better license CC0

* rlDrawMeshInstanced first attempt

* rlDrawMeshInstanced OpenGL 3.3 and VAO checks

* rlDrawMeshInstanced GetShaderAttribLocation; comments

* example instanced shader

* RLGL_STANDALONE RAYMATH_STANDALONE Vector4

* apply suggested naming changes; add instanced mesh example

* remove orphan variables

Co-authored-by: codifies <nospam@antispam.com>

This function was renamed for consistency in raylib 3.0, just unified all examples to use TextFormat() instead of FormatText()

* Make raymath naming and functions more consistent

* Minor fixes

* Fix examples

* Fix Physac

* New naming rules

* Apply naming to Quaternion functions

* Apply to models.c

* Remove *MulitplyValue / *DivideValue

NB glsl100 shader needs testing on "bare metal"

Co-authored-by: codifies <nospam@antispam.com>

It seems something is not working properly...

Co-authored-by: codifies <nospam@antispam.com>

head can't think of any improvement I could use on the shaders for
version 120
This has been tested on Linux (Desktop) requires testing on a Rpi

Co-authored-by: codifies <nospam@antispam.com>

Tested on Raspberry Pi... Just note that platform is very limited by GPU...

* Removed Unused Uniforms

uniform vec3 viewUp;
uniform float deltaTime;

* Removed Unused uniforms

uniform vec3 viewUp;
uniform float deltaTime;

* Updated Source

  Added   - #define PLATFORM_DESKTOP line for desktop users.
            This now will correctly find the proper glsl version for the raymarching.fs file.
  Removed - Uniforms --> deltaTime and viewUp. Including the code that was setting them.
            They were never used and they were triggering a log warning.
  Removed - The const from both screenWidth and screenHeight.
            Now they can be used to update the shader resolution when screen is resized.
            NOTE : This is a quick fix and probably not the best idea.
  Added   - IsWindowResized() to check if screen is resized.
            If window is resized then width, height and shader resolution are updated.
  Changed - MIT tag at bottom right color value to BLACK. Now it's easier to see.

* Closer Match to original code

* Removed the PLATFORM_DESKTOP Define

Contributed simple shader example

* Update year of copyright notices

* Fix mistake in comment

* Fix typo ("algorythms")

* Replace tabs with spaces

* Remove trailing whitespace and fix mistake in comment

* Fix ExportImageAsCode missing comment rectangle corner

* Replace tab with spaces

* Replace tabs with spaces

Contributed by ProfJski

Now shader uses `fragTexCoord` that are the full screen texture coordinates normalized, instead of `gl_fragCoord`, the unnormalized screen coordinates

Also changed path to shader back to what it was originally.