[aquaria] Enabled Windows compiling with Visual Studio

[Pontos]

First of all, it seems that some of the code you added (Part of what is 
not specified for msvc only) finally made the build to work on windows, 
even when compiling with Mingw. I can confirm that before this the game 
would compile with no errors (at least for me) thanks to the changes I 
made a few days ago, but the exe would simply crash. It runs now, thanks :)

Just a few remarks:

If Ryan ends up adding the libraries for MSVisualC you supplied, then 
please change the lines "elseif(WIN32)" with "elseif(WIN32) if(MSVC)   
...   endif(MSVC)"  in the SDL and OpenAL sections of CMakeLists.txt, 
given that the libraries you added are compiled with MSVisualC (Which 
btw, are static and not shared).
I can provide GCC-made libraries with the necessary changes in the 
CMakeLists.txt if Ryan agrees as well, which would make use of what I 
mentioned above.
Also, the line IF(CMAKE_GENERATOR MATCHES "Visual Studio") you added for 
FreeType2's compiling flags can be replaced by IF(MSVC) since the result 
is the same.
> I noticed that Pontos removed the contents of GLAPIENTRY for Windows
> as well, and I added APIENTRY back for VS since that's how they're
> defined in the new gl.h.
I did not remove it, I added it for Windows in fact.
The definition of GLAPIENTRY was only being used if (BBGE_BUILD_UNIX) 
was defined, meaning it was being ignored in Windows builds. I changed 
that so it works with both (BBGE_BUILD_UNIX) and (BBGE_BUILD_WINDOWS).
You should change the #ifdef _MSC_VER line into #ifdef _WIN32, since the 
new definition in gl.h is not limited to MSVisualC.