Added drawings of reaction families in ChemBioDraw format.

These are useful for visualizing what the various reaction families
represent.
Add Cdd atom type to *3 in Intra-R-Add-Enxocyclic reaction family.
Added some comments to the longDesc fields.
Merge remote-tracking branch 'origin/master'
Fix minor syntax problems caused by space, also group definitions are case sensitive(Cdd)!
Forbid triple bonds in 3- and 4-membered rings.

We don't have meaningful ring corrections for these, so they end up being
*far* too stable if allowed.
Until QM thermo, or better ring corrections, become the norm, I think it's probably best
to forbid these structures.