CompressureManifest.__repr__() reformat

[AudreyBeard]

The CompressureManifest.__repr__() function prints arguably too much info - it should do something like:

• version
• workdir
• sources:
  • number of encodes
  • number of reversals
  • number of loops
  • number of slice schemes

[AudreyBeard]

This issue is out of date and so describes "current" behavior that is no longer true. While the compressure.persistence.CompressureManifest.__repr__() method may need some work, it's not accurately captured in this ticket. Closing for now