Planning to promote raudio module as a simple and easy-to-use front-end for the amazing mini_al library, so the name change.

Name comes from raylib-audio but in spanish it also remembers to word "raudo", meaning  "very fast", an analogy that fits perfectly to the usefulness and performance of the library!

Consequently, raylib version has been bumped to 2.4-dev.

Wait for input events passively (sleep) instead of polling events actively every frame

-DBUILD_SHARED_LIBS=OFF == -DSHARED=OFF -DSTATIC=ON
-DBUILD_SHARED_LIBS=ON  == -DSHARED=ON  -DSTATIC=OFF

Fixes #626.

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

NOTE: These changes break the API (parameters order)

Homebrew doesn't ship 32-bit libraries anymore, so using both
-DUSE_EXTERNAL_GLFW and -DMACOS_FATLIB with a Homebrew GLFW would fail.
With -DUSE_EXTERNAL_GLFW=OFF, this is not a problem, but I think keeping
it off by default makes more sense. If someone wants universal
libraries, they can just toggle it.

Remove that link_libraries_to_executable() hack and defines a proper
raylib target that can be used with target_link_libraries.

The same target is also available for external (user) code by using
find_package(raylib).

This results in:

- Remove hardcoded build directories from examples and games CMakeLists.txt
- Allow rlgl_standalone and other special examples to be built easily
- Allow CMake projects to find_package(raylib instead of fiddling with pkg-config
- Makes code a little more maintainable
- Fixes #471, #606.
- Makes code less confusing by removing the double use of PLATFORM (#584).

Note that this is still not _The Right Way_(TM), because normally
raylib-config.cmake (or its includes) would be automatically generated.
I didn't manage to get that to work though, so I went the easier route
of just wrapping pkg_check_modules for consumption by find_package.

also makes one configuration shared-only

dr_flac is not built on i386, because GCC 4.8 complains about asm("cpuid"
clobbering ebx, as it's using ebx for PIC.

Instead of downloading a newer GCC (and multilib),
disable FLAC for that one configuration...

as well as -DUSE_EXTERNAL_GLFW.

Nips issues like #584 in the bud.

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

Also added new compilation FLAGS for that pourpose

I would have liked config.h to be selected by include dir configuration,
but this way is less intrusive.