"Try the stupidest possible thing" attempt to get catalog properties to wrap properly.

This doesn't really work, but I think it at least catches the appropriate structures that would need to be amended.
Moved wrapping logic to _make_catalog, inspired by Chris B

Untested. Completely untested.
Now I shift the low values upwards, and make a copy of index array.

This *has* been tested, and seems to work!
Reverting un-needed changes to dendrogram.py
Specific Error catching, rather than generic `except:`
Style cleanup for comment about wrapping structures.
Wrote a test for wraparound catalogs.
Merge pull request #121 from tomr-stargazer/wraparound_analysis

Simple fix for incorrect "wraparound" catalog properties