Rename test_basic.py to indicate we're doing timings.
Cleanup timings script.
MPI_Comm_create must be called on all engines

when creating a new group.

See [MPI Docs](http://mpi.deino.net/mpi_functions/MPI_Comm_create.html)
for details.

Also fixes an incorrect assumption that engine ID == MPI rank.

closes #7
TEST: Adds tests for creating DistArrayContexts.
Merge branch 'odin' into feature/push-func-names