Move the "add to the history if it's changed" code.

Instead of adding to the history of everything if anything has changed,
we now only add to new items.
The "has it changed" detection is currently broken, because old data is read into 
an incompatible format somehow.

This correlates with a commit in the RMG-Py repository.
Remove an un-needed function (convertKineticsToPerSiteBasis) from tsGroups.py
Convert H_Abstraction/TS_groups.py to use new DistanceData() class.

This file has been read in and written out by the script, so formatting should be consistent
(i.e. future diffs should be real changes).
Trained some transition state distances!
Convert H_Abstraction/TS_training.py to use new DistanceData class.

Conversion using a scrip to ensure consistency in
the changes.