Changes to forbidden structures in anticipation of universal database

Mostly have to do with how singlet and triplets can no longer be the same
group.

-change N_birad_RsRs to N_monorad_3singleBonds and clarified definition
-split N_birad_RsRsRs into two groups N_birad_triplet_2singleBonds and
N_birad_singlet_2singleBonds
-split Carbene_D into Carbene_D_singlet and Carbene_D_triplet
-split Carbene_S into Carbene_S_singlet and Carbene_S_triplet
Changed thermo groups to separate singlet/triplets

In anticipation of universal database conversion, I have changed all
groups which had {2S,2T}

in thermo_radicals:
Split RJ2 into two separate groups at L2 level: RJ2_triplet and
RJ2_singlet
Create new groups: CJ2_singlet, Oa_singlet, SiJ2_singlet, SJ2_singlet, and
NJ2_singlet and L3 level
Create new groups: CsJ2_singlet, CdJ2_singlet and L4 level
Create new groups: L5: CsJ2_P_singlet, L6: CsCsJ2_singlet
Create new groups: L7: CCJ2_singlet

Promoted up (L6 to L5) the following triplet groups and deleted the
immediate parent which was only to distinguish between singlet and
triplet:
-L6: CH2_t
-L8: CCJ2_t
-L7: PhCH_t
-L7: AllylJ2_t
-L6: CCdJ2_t
-L6: CdJ2_Sd_t
-L4: Oa_t

Moved the following groups in the tree to under the RJ2_singlet branch:
-L6: CH2_s
-L8: CCJ2_s
-L7: PhCH_s
-L7: AllylJ2_s
-L6: CCdJ2_s
-L6: CdJ2_Sd_s
-L4: Oa_s

-change adjlist for CO from double bonds to triple bond with singlet birad
on both C and O (no lone pairs, oxygen's lone pairs will be added during
conversion)
-moved to L2 level because it will no longer be a birad/doesn't fit under
current tree scheme
Fix N3sH2 group in Abraham solvation group since it was identical to group Cb.
Fix some syntax errors and typos in thermo radical groups.
Fix identical groups in thermo groups group.py.