Update ez_setup.
Fix .travis for master.
Merge branch 'pmg3'
Update version # to 3.0.0!
Fix setup.py.
Fix to_dict property deprecation.
Fix missing PMGSonable for Incar and Potcar.
Fix for random test failure due to inexact json dumping.
Add optional requirements in a separate file.
Update trove classifiers to include Py3k.
Fix classifiers.