Subtraction of two compositions removes species with amt == 0
Merge branch 'master' of github.com:materialsproject/pymatgen
Add gulp to circleCI.
Try a really dumb fix.
Fix bad bush.lib path.
Seriously, why are people still not using the with context and leaving file
pointers open without closing them.
Fix Tersoff potentials for gulp. Whoever write command line utlities better make sure
their code runs EVERYWHERE and not just on their own computer.
Add aconvasp for test.
Add aconvasp path to circle CI.
Do verbose nosetest in CircleCI so that I know what is being skipped.
Add main python site-packages to PYTHONPATH for circleci.
Updated dependencies doc.
 Add list of required_files to the Nodes of the Flow
 Fix typos
Allow POTCAR directory to be unzipped or bzipped
Use ISYM=0 by default for NEB runs
Make neb input set by default not write dos or chgcar
Camelcase for Tersoff_pot and BuckinghamPotLewis BuckinghamPotBush merged
BuckinghamPotLewis & BuckinghamPotBush classes are combined into BuckinghamPotential and removed.
Referecen to Lewis buckingham potential added into BuckinghamPotential