Changed a few things but most importantly textures seem to work now.
* D-ified some code (IIRC.)
* Textures now seem to work correctly.
* Text seems to work correctly.
* Using the D interface for the lodepng library now, instead of FreeImage.
* Using gdc instead of dmd (for some reason dmd wouldn't build the project.)
* Added conditional compilation to util.d:load_png_texture() for FreeImage, SDL_Image, and lodepng. lodepng is the default as it's the only version that displays textures correctly. This can be changed in package.json. If someone knows how to fix the FreeImage or SDL_Image versions, please do so that I can eliminate the hacky lodepng D interface.
* Various small changes that I can't remember.
Updated README.md