Merge pull request #4 from gotracker/updates

update errors package

Merge pull request #3 from eliasdaler/main

Various things to make it possible to run on wasm and macOS

Merge pull request #2 from gotracker/oldeffects-fix

IT flag decode fix, go 1.18 upgrade

Further fix for block reading

Fix for misreading some songs special blocks.

Support for decoding IT/OpenMPT blocks

Support for note-sample keyboard decode

Merge pull request #1 from gotracker/it-file-support

It file support

better messaging around unusual instrument headers

Further XM packing aggressiveness fixes