Create a `copy` function for entries

Allows the copying of an entry. This is needed
for a reaction family template to be copied.
Use a copy of the family template for the TS template

`transitionstates.py` used the templates from the reaction
family, however this is not desired since the transition states
and reaction family trees can be different. Creating a copy of the
family template allows the transitionstates template to be used without
affecting the reaction family.