Create OpenBabelParser to convert OpenBabel OBMol to MDAnalysis Universe by parsing atom attributes

[lunamorrow]

The first step of this OpenBabel converter will be to convert OpenBabel OBMols to MDAnalysis Universes. This will enable the indirect parsing of over 100 file types into a format that MDAnalysis tools can analyse.

After discussion (see #5), both the planned implementation and order of development has been modified. The OpenBabelParser will take an OBMol and correctly convert its attributes to an MDAnalysis Universe, not including positions (supplied by OpenBabelReader #5). This Class will need to account for different attributes in OBMol objects formed from different file types, and will exploit the OpenBabel python wrappers for easy access of attributes. The resulting Universe can be analysed as is, or modified.

For more information and suggested implementation please see GSoC Project.

[lunamorrow]

Working here @hmacdope