remove pre-2.0 compatibility stuff

[Jojo-Schmitz]

there's probably quite a bit more, but these are the obvious places

[lasconic]

Ideally, it would be great to regroup all this stuff in a single file instead of delete it. In a short discussion with Werner, he suggested to create a completely separated file to load press 2.0 files, something similar to the importxml files.

[Jojo-Schmitz]

OK, so I've for now just removed 114 > mscVersion() < 206, i.e. all the post-1.3 and pre-2.0.0 stuff.

oops, looks like a lot of the mtest files are pre-2.0.0, mscVersion() < 206

I can go ahead and fix them, if this PR in General is going into the right direction, otherwise I'd rather not invest the time. Just let me know.

[lasconic]

I believe it does. Only little problem is that we will need to update the test over and over again if we increment the format numbers like we did between 1.3 and 2.0.

[Jojo-Schmitz]

Well, we'd need to do it again for MuseScore 4.0 ;-)
We may need to do some mtests files again due to other test failures caused by format changes, but that was the case during 2.0 development too.

Question is which version to use to rewrite them now, latest master or plain 2.0.0, or something in between?

For now I've just changed them all to 2.07 using sed

[Jojo-Schmitz]

sorry, somehow I managed to fat-finger this PR. New on at #2581