Basically, formating review and some variables naming to follow raylib conventions.

* Working build

* Fix build again, stop deleting files

* Hotfix crash, needs investigating

* Remove VS2015.UWP, I cannot update the project

* Lots of UWP work, added keyboard and mouse press support. Still need to finish scroll wheel, mouse position and cursor hiding, plus other stuff that I haven't seen yet.

* Implemented a ton more things, added BaseApp.h to provide common code to UWP apps.

* Remove constant window dimensions

* Enable and Disable cursor support.

* Actually use mouse delta

* Gamepad Support

* Cleaning and small tweaks

* Restore original example.

* Update comment

* Use 'Messages' to handle the cursor functions so code is more portable.

* Comment

* Comment unused message fields and use vector for mouse pos instead.

* Move messages to utils.h and use messages for everything. No more plat-specific code in raylib.h

* Working build

* Fix build again, stop deleting files

* Hotfix crash, needs investigating

* Remove VS2015.UWP, I cannot update the project

* Lots of UWP work, added keyboard and mouse press support. Still need to finish scroll wheel, mouse position and cursor hiding, plus other stuff that I haven't seen yet.

* Implemented a ton more things, added BaseApp.h to provide common code to UWP apps.

* Remove constant window dimensions

* Enable and Disable cursor support.

* Actually use mouse delta

* Gamepad Support

* Cleaning and small tweaks

* Restore original example.

* Update comment

* Use 'Messages' to handle the cursor functions so code is more portable.

* Comment

* Comment unused message fields and use vector for mouse pos instead.

* Move messages to utils.h and use messages for everything. No more plat-specific code in raylib.h

* Tested some desktop stuff and added projection matrix updates for window resizing.

* Fixed big bad mouse bug

* Fix alt buttons and add hack to combat flickery key presses (far from perfect)

* Remove debug code

* Final commit

* Well, so I thought

* Wow, i am bad

* Remove packages folder

* Remove useless include

* Apply requested changes and fix linux build

* Try to stop packages folder

* Have we fixed the formatting properly?

* Third time's the charm?

* Where did this come from?

* Re-fix

* Autoformat is gonna kill

* Fixed XBOX ONE Support

* Fix tabs

Users can define their custom memory management macros.

NOTE: Most external libraries support custom macros in the same way, raylib should redefine those macros to raylib ones, to unify custom memory loading. That redefinition is only implemented as example for stb_image.h in [textures] module.

funopen is only needed on Android, so declare it
only there. This fixes following MinGW build failure:

utils.c:50:7: error: conflicting types for ‘funopen’
 FILE *funopen(const void *cookie, int (*readfn)(void *, char *, int),
       ^~~~~~~
In file included from utils.c:45:0:
/usr/include/stdio.h:586:7: note: previous declaration of ‘funopen’ was here
 FILE *funopen (const void *__cookie,
       ^~~~~~~

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

NOTE: These changes break the API (parameters order)

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

Not sure if this ever worked, but now it at least compiles.

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).

I think is clearer this way...

Trace log messages could be configured with this function to select wich
ones are shown

Let the user choose if using rres external library

...to avoid possible conflicting symbols

Replaced old GetExtension() function
Make IsFileExtension() public to the API

Working in modules configuration flags...

- Renamed WritePNG() to SavePNG() for consistency with other file
loading functions
- Renamed WriteBitmap() to SaveBMP() for consistency with other file
loading functions
- Redesigned SaveBMP() to use stb_image_write

Start removing old rRES functions.

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.

Useful to save small data files (configuration and so)
For bigger files, external data storage should be used (SDCard)