Wider Version Support And Higher Compression Mode

This supports large JPEG files by default and also has a new mode --enable-best-ratio-slow-decompression that can decrease decompression speed but result in a few extra percent compression gains

The lepton-fast.exe binary makes .lep files that are fast to decode by using multithreading
the lepton-small.exe binary makes .lep files that are slightly smaller but may not be decoded in parallel