Update bundled NWChem version to latest

[ohlincha]

Think the bundled version is 6.5 whereas current is 6.6 with a long list of patches added

[dustinrb]

The bundled version is 6.3. Unfortunately, NWChem no longer supports compiling without MPI. When bundling 6.6, either we will have to create an unsupported build or add MPI as a dependency and update the submission script generator.

In the future, I would prefer stripping NWChem from ECCE and providing a ECCE-compatible rpm/deb.

[ohlincha]

If that's the case, NOT including nwchem indeed seems like the most sensible choice. Debian and Ubuntu already include nwchem. Not sure what that case is on Centos and Fedora.

The one advantage of bundling nwchem was that it provided an easy way of quickly checking whether everything was working ok.

Closing.