tools: update mei40To50.xsl

[musicEnfanthen]

This PR updates the mei40To50.xsl to include the latest changes from the main repo for v5. That is, it adds transformations for line.form and line.width on arpeg. Additionally, it resorts some of the existing transformations in the main part to have element- , attribute- or value-based transformations in one place (fingerprint is moved up, Bagpipe is moved down).

[musicEnfanthen]

Seems to work, at least according to the unit tests:

Test cases are here

```xml ```

[bwbohl]

do the test cases also live somewhere else? maybe alsongside the xsl in a test folder?

[musicEnfanthen]

See #37