fitPolycyclicThermoGroupsFromThermoLibrary script added

This script takes thermo libraries and fits new polycyclic groups from them.
It saves the all of the polycyclic groups to the file `new_polycyclic.py`.
  This file can be used to overwrite the original polycyclics thermo groups
 file in `input/thermo/groups/polycyclic.py`.

**IMPORTANT:** It averages any data that is found within the libraries,
 but will overwrite any old thermo data.  If old data is trustworthy,
this script must be modified

Uncertainties for the groups are calculated as 2s, where s is the sample
 standard deviation

Author: connie