when running execute, boundaries do not have to be flat (probably not working yet)
when running execute, boundaries do not have to be flat (probably not working yet)


Former-commit-id: 929d1d8196e74be387cfafc62f86944b02168ae4
Former-commit-id: 830cbe4f8fd1f25b67aaf6723c039c269b274685
TomTranter/OpenPNM,amdouglas/OpenPNM,stadelmanma/OpenPNM,amdouglas/OpenPNM,PMEAL/OpenPNM