Fix possible crashes in resize and crop filters with high bitdepth input
Replace gf_malloc with regular malloc in mp4 muxer

It was used as a workaround for a bug that only existed in the GPAC repository
for a few weeks back in 2010. There's no reason to keep it anymore.
Fix compilation of shared library for Windows with original MinGW toolchain
Add L-SMASH support as preferable alternative for MP4-muxing