A new Untis Parser API (+ improvements to the automatic parsing)

[pixelcmtd]

Parsing the actual <table> of substitutions is quite a difficult task, because not only different Untis versions, but just different schools in general always have different ordering.

The current Parser API makes it possible to plug in your own parser if your school uses a format that isn't parsed correctly quite easily. However, it would be preferable if it just worked, and using your own parser would be a bit easier.

Both should be possible to achieve at the same time and I got some ideas on how to do this, but I'll still need to think about them for a while.

[pixelcmtd]

In 0.1.0-alpha.4, I introduced the new API. Now only improving the automatic Untis parser is left to do, but that can be dealt with in a minor release.

[pixelcmtd]

This is especially important, since even for the public test account the parsing is wrong rn.