Changes related to mei version 5.0

[martha-thomae]

• Use MEI version 5.0 as it is a stable release where @dur.quality is already present (we can stop using the developer version). Moreover, the 5.0.0-dev is not the developer version anymore so there is an issue with the version we are currently using.

  • Change schema from to href="https://music-encoding.org/schema/dev/mei-Mensural.rng" to href="https://music-encoding.org/schema/5.0/mei-Mensural.rng" (in lines 2 and 3 of the processing instructions: xml-model)
  • Change mei/@meiversion from 5.0.0-dev to 5.0

• Remove @num and @numbase in elements that already include a @dur.quality