Feature request about importing 16-32 bit PNGs

[PeterPedro]

Just a quick request to add support to Magicavoxel for importing PNG files that are 16 and 32 bits, maybe just convert them down to 8, this is because if the files are 16 or 32 bits I have to keep converting them with other program before importing them into MV otherwise they wont load.

Edit: to add that I might be wrong about the bit depth causing the issue, but certainly some PNGs have issues when loading into MV