Fixes

• Handle / being used instead of . as package separator
  • E.g. net/minecraft/class_5272 is now remapped correctly to net/minecraft/client/item/ModelPredicateProviderRegistry
• Fix some classes causing errors when trying to remap (Fixes #7)

New

• Separate fabric integration and common remapping code
  • Adds web subproject for remapping text to different mappings/versions
• The checksum of all files is now verified on download
  • Intermediary/Quilt mappings always use sha512
  • Mojang mappings always use md5/sha1
  • Yarn uses sha512 on modern version, but falls back to sha1 for 19w02a, Combat Test 4 and all versions older than 1.15 (except 1.14.4)
• Some fixes to support more versions
• Mapping/Metadata downloads will be retried 3x before being cancelled, if:
  • The server returns a non 2xx response code
  • Checksum verification fails