Made small changes to the thermolibraries.
a) Modified the Cd-(Cd)(Cd) thermo group which appears to be 7 kcal/mol too low
b) Added a HBI for indenyl
c) Added ring correction for cycloheptatetraene
Adding the option to set max C atoms for a Pdep Network

This option provides more flexibility to determine if we need
to treat a reaction as pressure dependent. Ideally we should not
recommend using this option since whether to treat a reaction as
Pdep or not depends on the total number of atoms in a reaction (i.e net degree
of freedome determines whether a molecule can undergo internal relaxation).

However for some practical consideration when your fuel is unsaturated
and leads to a lot of aromatic species (mostly heavy atoms due to decrease
in saturation) we might want to specify the Carbon number or total number of
Heavy atoms (not yet implemented).
New criterium for intra_R_Add_Endocyclic and intra_R_Add_exocyclic
Consider only addition reactions when the rad and double bond are not part
of two different rings that have 2 or more atoms in common.x
Rate rules for recombination reactions of H with CPDyl (and similar structures)
Correcting Alkene+OH addition arte coefficient

The previous estimate was x10 too fast, not sure what went wrong.
Probably when I flipped it using the thermochemistry it resulted
in an error. Replacing the rate by Zador et al. propene + OH
rate coefficient.
Merge branch 'master' of https://github.com/GreenGroup/RMG-Java
Few additional rate rules for intra H migrations. Mainly related to the currently discovered pathways to benzene from butadiene + allyl.