[textures] Added SaveKTX()
[rlgl] Exposed rlGetGlTextureFormats()

Added note on KTX 2.2

REVIEWED: ExportImage()
REVIEWED: ExportMesh()
ADDED: ExportWave()
REMOVED: Internal funcs: SavePNG(), SaveBMP()

NOTE: These changes break the API (parameters order)

See raylib/examples/textures/textures_image_9patch.c for how to use `DrawTextureNPatch` function.

Added support form vertical and horizontal 3-patches.
Corrected the distortion caused when destRec size is smaller than 4x4. Now even 1x10 or 0x0 sizes are drawn correctly.

Added DrawNinePatch() function implementation.

Note for me: Replace All is NOT your friend...

Library consistency rename... yes, I know, it breaks the API...

This function was added in text module as GenImageFontAtlas()

Added: data to CharInfo struct
Added: LoadFontData()
Added: GenImageFontAtlas()
Removed: LoadFontEx()
Removed: LoadTTF() [internal]
Some code tweaks

- GetImageData()
- GetImageDataNormalized()

Reviewed: GetImageData()
Reviewed: ImageFormat()

ImageDraw() code tweak

Added note idea on ImageFormat() for future redesign (to support
16bit-32bit pixel-formats)

Not used in raylib this mechanism

It seems TCC was not casting correctly int values to float in some
specific situations

Did this ever work? Surely, doesn't look like it...

- Preparing MP3 files support
- Jumped version to raylib 2.0-dev (too many breaking changes...)

- Some examples tweaks
- Reviewed ImageFormat()
- Use float for text fontSize

That way, a user needs only to touch a single file to configure what
features raylib is built with.
Include guards are left out intentionally, because config.h should only
be included in source files, not headers.

Later on, config.h can also define the raylib version (#461).

Now PLATFORM checks only used on core and utils modules

Renamed SaveImageAs() to ExportImage() for consistency on what actually happens with data.

Not sure if math is ok... just left a commented piece of code that uses pre-multiplied alpha.

Supported UTF8 range equivalent to [128..255] (80h..FFh)
Exposed and renamed text function GetGlyphIndex()
Renamed spriteFont parameter name to simply font
Small security check on transmission mission ending screen

When changing image format, mipmaps are lost and regenerated from
scratch

Review rlLoadTexture() function to make it simpler, now OpenGL texture
glInternalFormat, glFormat and glType are retrieved with new function
GetGlFormats()

GNU C allows it as a compiler extension, but MSVC doesn't.