Fixed bug in drawing of Network PES.

The bug occurred when trying to condense the space occupied by reactant
channels (placed to the left of the unimolecular isomers). The condensing
caused the reactant isomers to move to the right; we just needed to shift
the entire PES back to the left so that it actually appears in the rendering
window.
Updates to convertFAME.py to make it work with new CanTherm.

Mostly updating the names of a few existing fields and the adding of a few
new fields.
Better handling of very large barrier heights in hindered rotors.

The partition function of a hindered rotor involves a modified Bessel
function of the first kind, I0(z). This function overflows above z = 700;
however, there is a nice series expansion for exp(-z) * I0(z) with less than
0.1% error above x = 100, so we now use that for very large z. (z = V0/2RT)
Add command-line option to control generation of plots in CanTherm.

You will now only get plots of thermo, kinetics, and k(T,P) values if you
provide the -p or --plot command-line argument. Note that you will still get
a drawing of the PES in pdep jobs either way.
Can now prune network in convertFAME.py using -x flag.

You use -x to specify an energy (magnitude and units) above which any
configurations or reaction barrier heights are removed during the conversion
of a FAME input file to a CanTherm input file. This helps crop some of the
more bizarre species that RMG-Java comes up with (e.g. triradicals), leading
to a more tractable PES.