- Expose all the configuration settings used by the quality presets to allow fine-tuning of edge detection.
- Changed default edge detection technique from luma to color since in my tests that always yields better results.
- Increased quality to ultra in default preset.
- Deleted the duplication of the fragment shader part of the lib, as I figured out how to include the lib twice with different defines for the vertex and fragment passes. That is necessary probably because discard cannot be used in vertex shaders in RetroArch, indicated in a comment in the lib as a possible restriction in some compilers.
- Include license headers to make clear that all my contributions are released on the public domain under the terms of the Unlicense. Anyone can do whatever they want with this.