Add missing imports necessary for kinetics database group fitting.
Add missing imports necessary for kinetics database group fitting.

I guess these were only used in bits of the code that are called from
RMG-database/kineticsGroups.py, but they're definitely needed for that.

chatelak/RMG-Py,KEHANG/RMG-Py,nickvandewiele/RMG-Py,enochd/RMG-Py,KEHANG/RMG-Py,faribas/RMG-Py,pierrelb/RMG-Py,nyee/RMG-Py,comocheng/RMG-Py,nyee/RMG-Py,pierrelb/RMG-Py,chatelak/RMG-Py,faribas/RMG-Py,comocheng/RMG-Py,enochd/RMG-Py,nickvandewiele/RMG-Py