Fix typo in Intra_R_Add_Exocyclic
Allow *3 to be Cdd in the DoubleBond group as well in Intra_R_Add_Exocyclic

The top level groups all allow Cdd atom type as *3, but we would not
descend the tree to get any decent data, because the double bond group was
defined as Cd only. Now at least we will get to a level two node, although
we have no relevant data below this.
Strip whitespace at end of lines
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.
Changed `1,3 Insertion CO2` to only insert in a CH bond

Currently only have data for CH bonds, but the group definition
allowed for CC bond insertion as well. Without data for such
insertions, estimates were used from the CH reactions, which were
much faster than expected. Unless this reaction is found to be
possible, the group will be defined for CH bonds only.
Add Methyl Butanoate seed mechanism from Huynh model to RMG- database . 
( Shock tube studies of methyl butanoate pyrolysis with relevance to biodiesel, http://dx.doi.org/10.1016/j.combustflame.2012.05.013)