v0.2.0: updates uberenv to new spack (#57)

* update to new spack develop

* add unzip package to docker

* updates for new spack

* fix missing uberenv inhertiance, tweaks to travis and docker build configs

* init const props needed for filter interface

* update spack compiles and pkgs for llnl systems

* variant is vtkh instead of vtkm

* try mpich for travis and avoid building cython

* expliclity use +mpi variant so we can trigger mpich

* quote spec when handing to uber