Fix reading of measures with custom bar line sub-type.

If a measure has, in one staff, a bar line with a custom sub-type, the sub-type is applied to the bar lines of all the staves of this measure.

Fixed in `Measure::read()`.
Add relevant test.
Merge pull request #1010 from mgavioli/Fix_reading_measures_with_custom_barline_type

Fix reading of measures with custom bar line sub-type.