Fix various issues with the atlas texture cache

[Steveplays28]

• Fix mipmapping issues with atlas textures loaded from cache
• Fix an occasional native crash when writing NativeImages to JSON
• Move some Mixin classes into packages
• Remove unused code
• Use enabled resource packs' names for the hash
  • Rename the .minecraft/.blinkload/mod_list_hash file to .minecraft/.blinkload/mod_and_enabled_resource_pack_list_hash
• Filter substrings from the mod/resource pack list instead of prefixes

Fixes #5.