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

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

Now it supports multiple maps one next to the other