Complete set of constants as specified in the WebGL, WebGL2 and extension spec.

All constants have their original names prefixed with GL_ in order to namespace the constants and were directly ported from the documentation on the Mozilla Developer Network. In some cases the documentation describes duplicate cases such as UNSIGNED_BYTE as both a data type as well as a pixel type. For that reason I've decided to prefix each with their type resulting in GL_DATA_UNSIGNED_BYTE and GL_PIXEL_UNSIGNED_BYTE.

My work is released under the MIT license.