Stop using getUsername() which is slow, deprecated, and about to vanish.

This is no longer used on the up-to-date RMG-Py and database, and using it
is slowing things down.
Display reaction family in voting reactions view.

As suggested in models issue 60.
A lot of things come from Glarborg/C3, which makes it less helpful than
telling you what type of reaction it is, but it's still somewhat helpful.
Don't make species that can't possibly match the chemkin file.

We would discard these pretty quickly anyway, but not until after we 
have generated the species thermochemistry and estimated their rates, which 
all takes time (especially with QM thermo and large cyclic things).

Now, by modifying the global isMoleculeForbidden method, we prevent
reaction families from making these reactions in the first place.

As suggested in models issue 69.