Moved all external libraries used by raylib to external folder inside
raylib src. Makefile has already been update and also the different
includes in raylib modules.

This is a first step toward a bigger project. Some modules could be
ported to header-only to be used as standalone.

Support render texture size different than screen size

Now it's possible to render to texture, old postprocessing system will
be removed on next raylib version.

Specially useful on default font scaling

Corrected some code details

Updated functions:
Image GetTextureData(Texture2D texture);
void *rlglReadTexturePixels(Texture2D texture);

LoadTextureEx() - Simplified parameters
UpdateTexture() - Added, allows updating GPU texture data

Added (or completed functions):

Image ImageText(const char *text, int fontSize, Color color);
Image ImageTextEx(SpriteFont font, const char *text, int fontSize, int
spacing, Color tint);
void ImageFlipVertical(Image *image);
void ImageFlipHorizontal(Image *image);
void ImageColorTint(Image *image, Color color);
void ImageColorInvert(Image *image);
void ImageColorGrayscale(Image *image);
void ImageColorContrast(Image *image, float contrast);
void ImageColorBrightness(Image *image, int brightness);

Renamed functions (for coherence with new ones):
- ImageConvertToPOT() -> ImageToPOT()
- ImageConvertFormat() -> ImageFormat()

New functions added (IN PROGRESS):
- ImageCopy()
- ImageCrop()
- ImageResize() (Uses stb_image_resize.h)
- ImageDraw()
- ImageDrawText()
- ImageDrawTextEx()
- ImageFlipVertical()
- ImageFlipHorizontal()
- ImageColorInvert()
- ImageColorGrayscale()
- ImageColorContrast()
- ImageColorBrightness()

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

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

Corrected issues with textures loading

Complete review of matrix rotation math
Check compressed textures support
WIP: LoadImageFromData()

- Camera system moved to a separate module [camera.c]
- WIP: Added customization functions for camera controls
- Added custom shaders support on batch drawing
- Complete redesign of textures module to support multiple texture
formats (compressed and uncompressed)

Moved functions: LoadShader(), UnloadShader()
Add support for PVR textures compressed/uncompressed
WIP: Detect available extensions for compressed textures

Support multiple texture formats (uncompressed and compressed)
Postprocessing shaders support
Model struct redefined and improved
Extended loading functions for Textures and Models
Simplified functions: DrawPlane(), DrawQuad()
Deleted functions: DrawPlaneEx(), DrawGizmoEx()
Now Text module only depends on Textures module
Shapes: Reviewed functions to low lines/triangles usage
Removed useless tabs and spaces around code

Shader system has been completely redesigned
Added support for multiple texture color modes

Corrected some bugs on the way...
Automatically convert textures to POT on RPI and WEB

Added PLATFORM_WEB support (emscripten-webgl)
[audio] Added LoadSoundFromWave()
[textures] Added LoadTextureFromImage() to replace CreateTexture()
Some TraceLogs edited...

This is a huge update. Check CHANGELOG for details

Set default raylib to use OpenGL 1.1 (compatibility issues on ATI cards)

Check CHANGELOG for a detailed list of changes

View CHANGELOG for a detailed list of changes