Removes miniz as a bundled dependency, relies on our own zlib instead.
Includes a couple commits ahead of `v1.0.1` tag to fix MinGW builds.
(cherry picked from commit 46d3effa99)
-Improvements to texture importer
-Proper detection of S3TC compression modes, and added all modes to Image
-Fixes to non-power of 2 compressed textures, which should all be supported by GLES3