Mod files

[phw]

This adds support for loading various tracker module formats. Loading and saving the songname (as title tag) is supported for most of the formats that support storing this information in the file.

Calculation of playback duration is currently not implemented. This could be added in the future, but requires more extensive parsing of the various formats (including in some cases several different format versions).

I tested this with some files from my collection and additional files in various formats from https://modarchive.org/