WIP: lammpslib.py

Open username-removed-261087 requested to merge tdaff/ase:lammpslib into master

lammpslib.py provides a Calculator interface to LAMMPS via it's bundled Python interface.

Interpretations of the licences previously prevented the code being distributed with ase, however this has now been resolved in Issue #37

This is a modified version that was developed as part of https://github.com/libAtoms/pymatnest and has extended functionality, including bonds.

TODO: add tests TODO: make code functional with Python 2.6, 2.7 and 3.x