Fix H2CC electronic state in USC-Mech-ii thermo database.

We'd attributed it to the triplet, based on the reactions,
but this is the thermo for the singlet. 
(We should have an inter-state crossing reaction in our models)
importOldDatabase.getUsername() now works on posix systems without os.getlogin()

This solves a problem when running on one of our clusters, which would 
otherwise give an OSError when you try to call os.getlogin()