- Renamed function rlEnableFBO() -> rlEnablePostproFBO()
- Defined struct FBO
- Moved FBO creation to function: rlglLoadFBO()
- Reviewed rlglReadTexturePixels(), trying to support OpenGL ES -IN
PROGRESS-

Time measure on Windows platform done with:
QueryPerformanceCounter()
Testing required!

Corrected bug on defaultFont.size
Renamed funcs:
ImageConvertFormat() -> ImageFormat()
ImageConvertToPOT() -> ImageToPOT()

...shapes based on LINES, TRIANGLES and QUADS. Now the calling order of
the drawing functions is respected!

strdup() is not a C99 function (it's POSIX), not available in emscripten

On OpenGL ES it was set to use GL_CLAMP_TO_EDGE wrap mode for textures.
On LoadOBJ() texture coordinates were wrongly Y-flipped

[rlgl] Extensions strings loading was redone to avoid a Segmentation
Fault on Raspberry Pi

Splitted into:
UpdateCamera()             // Update only camera
UpdateCameraPlayer()   // Update camera and player position

Immediate Mode GUI (IMGUI)

- Trying to implement rlglUnproject() - NOT WORKING
- Tested GLEW alternatives: glad and glLoadGen - NOT WORKING

Useful to enable additive blend mode for particles

Requires raymath as standalone and GLEW

...shader loading security check

Added window drop files support

Now gestures system can be used as standalone module

Camera system can be used as standalone module

Now audio module can be used as standalone module

Shader functionality owns to rlgl, not core module

Added:
- LoadImageRaw()
- ImageCopy()
Renamed:
- GetPixelData() -> GetImageData()