Set properties on unit tests

Created by: dalg24

Slave machines used in automated testing get wildly oversubscribed, especially when allowing a number of concurrent builds >1

• Consider specifying how many processors a given unit test require
• Must act on MPI unit tests that have OpenMPI enabled (set OMP_NUM_THREADS environment variable and specify the number of MPI processes instead of using MPIEXEC_MAX_NUMPROCS)