Resolve "Repeat Signal does not work correctly with other metadata-based formats (OSBA, OMASA)"

Related to #80 (closed)

• The code contained many occurrences of isinstance(x, y) or isinstance(x, z). These were be simplified to isinstance(x, (y,z)).
• Some checks were only tested ObjectBasedAudio and the addition of OSBAAudio and OMASAAudio was missing, causing the reported error.
• No errors were reported in the audiotools.convert module when trying to trim or delay metadata-based formats (ISM, MASA, OSBA, OMASA) when they should have been.