pyne support
changed isotope -> nuclide
Iso -> Nuc
iso -> nuc
merged with staging
Merge branch 'pyne' into iso-to-nuc
commodity.* : style corrections
Merge pull request #709 from scopatz/pyne

Add's nuclide handling and nuc data access code from pyne.
Merge pull request #710 from scopatz/iso-to-nuc

Iso -> Nuc, isotop* -> nuclide*, etc.  Just identifier and comment renames.
commodity_producer.* : style corrections.
Merge pull request #716 from rakhimov/google_style

commodity_producer.* : style corrections.
Merge branch 'develop' into integration_testing
Remove inheritance from Model class, following the develop branch.