Increase toc depth for API docs.
Refactor atomic_scattering_params.
use overkill strategy in molecule matcher if can't find matched elements
Merge remote-tracking branch 'origin/master'
Update README.
Add labels to axes of XRD plot.
Fix unittest for xrd plot.
Cleanup.
Merge branch 'master' of github.com:materialsproject/pymatgen
Support float wavelengths in XRD calculator (allows for electron and neutron
diffraction analysis as well).
Very minor refactoring and more comments.
Minor doc change.
Minor doc updates.