\bar isn't handled properly #124
Description
If \bar is used within a bar no in-measure barline is created but the barline style of the right barline of the current bar is changed.
If \bar is used to modify a current barline then an additional empty bar is introduced, with its right barline matching the requested style.
In the latter case we should update the previous bar (if it's not the very first bar, in which case it should probably be skipped), in the former we should probably insert the barline at the current point in time, with location="middle". At least that's what the documentation says: https://usermanuals.musicxml.com/MusicXML/Content/CT-MusicXML-barline.htm, but when adjusting a document manually to that, MuseScore 2.1 won't display the additional barline.