Separates MPI stdout / stderr.

Uses the --output-filename <prefix> option to mpiexec.
Refactors Makefile and improves engine test output.

Ensures that the proper exit status is returned to shell from mpiexec
call.
Put parallel output files in the .parallel_out directory.
First stab at a `reset_cluster` target.

Removes all engine modules that start with "distarray".

Probably needs refinement to get working fully.
reload -> reset
Don't ignore exit status for certain make targets...

And mark `test_engines_with_coverage` as .PHONY
Merge branch 'master' into bugfix/separate-mpi-output
No longer `eval()` user command in ipcluster.py.
Merge branch 'master' into feature/reload-cluster

Conflicts:
	Makefile
Merge pull request #229 from enthought/feature/reload-cluster

First stab at a `reset_cluster` target.
Fix a couple of .PHONY lines that were out of sync.
Documentation fix in utils.mirror_sort. PEP8.
Merge pull request #233 from cowlicks/utils-fix

Documentation fix in utils.mirror_sort. PEP8.
Merge pull request #234 from enthought/bugfix/fix-make-phonys

Fix a couple of .PHONY lines that were out of sync
Ignore .parallel_out directory.