erdc/proteus: 1.8.2

• remove air-water-vv and proteus_tutorial submodules. Not because those are being deprecated but because the main reason for having them as submodules was automated testing, and I think it's better to run the tests on those submodules separately. We might add them back using a test matrix or some other way to allow longer runtimes.
• remove conda os x test because it exceeds the time limit (could re-enable if we can get multiple cpu's)
• numerous updates to tests to ensure they work on linux and mac os x (despite not running on mac for travis)
• multiple changes to Makefile, setup.py, etc. to address changes in python packaging infrastructure
• changes to address Cython package updates. Mainly I switched to use language_level=3 (e.g. strict Python3) uniformly.
• fix deprecated np.int. Should just be int
• updates to PETSc options (naming)
• updates due to Chrono API changes
• FCT support in Richards model
• Some updates to CutFEM support for solid/air/water models

@cekees @abarua-ce and @jhcollins