Remaining feature discrepancy between TestSuite and ItsdbProfile

[goodmami]

The new TestSuite class in the itsdb module is meant to replace the ItsdbProfile class, but there are some remaining features that don't have an equivalent in the new class. Not all features are necessary, but some are important, and ItsdbProfile should not be removed until the features are covered. This issue is meant for tracking which features remain unimplemented.

• filtering on column values (see Replace delphin select with tsql queries (maybe) #138)
• mapping to a new relations file (e.g., ts.write(relations='.../relations'))
• incremental file reading/writing
  This would be particularly useful for process(), as the full processing results for a single table can take up gigabytes of memory

Also the following ItsdbProfile methods can be useful:

• exists()
• size()

[goodmami]

Incremental reading and writing is not necessary for #179, so I'm closing this issue. That feature is now tracked as #186.