bindbc-sdl Updates

[Mike Parker]

I've updated the BindBC bindings (to the Simple Direct Media 
Layer (SDL) library and its satellite libraries to support the 
following:

SDL 2.0.12
SDL_image 2.0.5
SDL_mixer 2.0.4

This is available in bindbc-sdl 0.16.0:

http://bindbc-sdl.dub.pm/

A few notes:

The SDL maintainers have moved to a system of labeling public 
releases with even patch levels and development releases with odd 
patch levels. SDL 2.0.12 is the first release of SDL under that 
system. The same goes for SDL_mixer 2.0.4. SDL_image 2.0.5 was 
released before it took effect.

There is no difference in the public API of SDL_image versions 
2.0.2, 2.0.3, 2.0.4, and 2.0.5, other than the value of the 
SDL_IMAGE_PATCHLEVEL constant.

SDL_mixer 2.0.4 added support for OPUS files. The only API 
changes aside from the patchlevel constant are a couple of new 
values for the Mix_InitFlags and Mix_MusicType enums.