move addThermoData out of the ThermoDatabase class
move addThermoData out of the ThermoDatabase class

It can be useful for other things or for outside scripts
 since it is very generic

Add a groupAdditivity flag to addThermoData set to False

Calls it with True if called from the GAV estimate in ThermoDatabase

nickvandewiele/RMG-Py,pierrelb/RMG-Py,chatelak/RMG-Py,nyee/RMG-Py,chatelak/RMG-Py,nyee/RMG-Py,pierrelb/RMG-Py,nickvandewiele/RMG-Py