Support for classical music tags introduced in iTunes 12.5

[YodaDaCoda]

With iTunes 12.5 (released 2016), Apple introduced a few new atoms/frames, to better support classical music. It would be great if taglib-sharp could support these tags.

• M4A:
  • ©wrk: Work (string)
  • ©mvn: Movement Name (string)
  • ©mvi: Movement Number (number)
  • ©mvc: Movement Count (number)
  • shwm: Show Work & Movement (0/1)
• ID3 (2.3, 2.4; MVN, MVI for 2.2):
  • MVNM: Movement Name
  • MVIN: Movement Number/Count