Fixed drawing of multiple rings in a molecule. Fused rings still broken.
Fixed multiple ring drawing again (fused rings still broken).
Improved fused ring drawing for one or two common atoms.
use rdkit drawing
Use rdkit to draw, excess code removed.
Cleaned up comments to reflect changes.
Merge rdkit into molDraw

molDraw now uses rdkit to draw molecules. The rdkit branch
was a start at removing openbabel and replacing it with rdkit.
Fix spin multiplicity calc in from rdkitmol.
Use rdkit instead of OB. Add from functions.
Adds kekulization for fromRDKitMol.
Removed OpenBabel dependence from writing gaussian input files.

We do the text manipulation (reading a .mol file, writing a .gjf) 
on our own now, instead of using OpenBabel.
May be slightly more fussy about the input .mol file formatting, but as these
are made automatically by RDKit it's unlikely they will change.
Removed OpenBabel dependence from writing mopac input files.

We do the text manipulation (reading a .mol file, writing a .mop) 
on our own now, instead of using OpenBabel.
May be slightly more fussy about the input .mol file formatting, but as these
are made automatically by RDKit it's unlikely they will change.
Remove CML from example input file.

Without OpenBabel we cannot read CML.
If we re-enable it, revert this commit.
Tweak the molecule drawing - make bonds a little shorter.

I think this looks a little better, at least on the molecules I tested it on.
Get the qm.molecule.rd_build to use the molecule.toRDKitMol method.

This reduces a lot of code repetition, although there were a couple of
minor differences between the methods. Namely:
 1) in the QM module we need to return a dictionary of mappings
 2) in the QM module we need to keep hydrogen atoms
Remove unnecessary imports.
Remove unnecessary SMILEwriter code.
Remove references to CML in rmg input file.

Add in references to SMARTS since we have that 
functionality.
Remove openbabel in favor of RDkit for database loading.

It is used for conversation of SMILES notation
to molecule, so RDKit is now needed instead of
openbabel.
Remove unnecessary openbabel code.