* Updated and checked for Python 3.5.\* compatibility.
* Element, Spin, Orbital and various other Enum-like classes are now actually
implemented using Enum (with enum34 dependency for Python < 3.4).
* Speed up Site creation by 20% for ordered sites, with cost in terms of
slightly slower non-ordered Sites. Since ordered Sites is the far more common
case, this gives significant boost for large scale manipulations of
structures.
* Alternative, more pythonic syntax for creating supercells via simply
Structure _3 or Structure_ (3, 1, 1).
* zeo++ fixes.
* More stable incar settings for MITMDVaspInputSet.