Get NWChem into master

I'm opening this pull request, because I think the NWChem parser is close to ready for master. This will save us the effort of going through the nwchem branch @cclib.

More than half of the SP and GeoOpt tests now pass, although many unit tests remain to be run and parsed.

I think we should wait with this merge until after 1.2, but after that please feel free to merge when you think it is ready.