Bug fixes

[CalebQ42]

• Fixes #220.
  • Additionally, if additional desktop actions are present, the Exec is replaced so it works properly.
• Fixes bugs caused by squashfs v0.6+
  • Forgot that v0.6 now does things more correctly so Open doesn't allow wildcards anymore, which broke some things.
• Added AppImage.ListFiles to goappimage to get around above.
• Changed build script so zig is not permanently installed and can be cleaned up afterwards
• Since I was already doing things with desktop files, also implemented fix I mentioned in #110.

[CalebQ42]

Added an additional fix for terminal appimages (#217) by setting wrapped appimage's stdin and stdout.