Corrected adjlist for USC-Mech-ii

The changeTripletToSinglet method in rmgpy/molecule/molecule
was used for the singlet radical cases. The method
changes the multiplicity to 1, but the adjlist still reports
the atom as having 2 unpaired electrons (instead of a lone
pair and an empty shell). I can't remember if this is what
we want of if this should have been corrected.

Should address #50.
Corrected the lone pairs for singlet radicals

Multiplicity is properly set, but the lone pair was
accounted for as 2 unpaired electrons.
A few additional corrections for USC-Mech-ii thermo: CO and C(T).