amanzi/ats: ATS Release 1.4.0

ATS version 1.4.0 is a major new release, with a complete revision of significant infrastructure within Amanzi and ATS. Little physics has changed, but the underlying multiphysics infrastructure has changed substantially, so this release affects developers more than users (though input files have changed substantially as well in this release).

• The new State model in Amanzi fundamentally changes what can be stored in State.
• The new Tag system in Amanzi required a rewrite of all ATS PKs to use Tags instead of multiple copies of State to deal with time-slices, subcycling etc.
• DomainSets were completely rewritten and updated to allow PKs to work on subdomains robustly. This is particularly important for multiscale and multidimensional models (e.g. the Arctic Intermediate Scale Model, the ADELS transport model for hyporheic exchange, etc)
• A complete pass through (nearly) all PKs and Evaluators was completed, standardizing a lot of documentation, use of the input spec, use of State and Evaluators, use of Keys and Tags, and more.
• Subcycling was generalized and now works with any PK/MPC.