Consider upgrading to support newest version of pylzss

[nik312123]

This project requires pylzss 0.3.4. The newest version at the time of this message is 0.3.8.

[m1stadev]

I temporarily rolled back the pylzss version to 0.3.4 with the latest PyIMG4 release because I have gotten reports from others of compression being broken with 0.3.8. If/when I release a new pylzss version that fixes these issues, I'll have PyIMG4 use that version.