Improve efficiency of test_look_at_neural_V1

[deirdre-k]

Issue

test_look_at_neural_V1 requires so much memory that it leads to some test jobs being killed in OpenMind (see #996, #950, error below). It's already marked @pytest.mark.memory_intense, which stops it from running in Travis, but it appears to be failing even in resource-rich environments.

Task

Either (a) improve the efficiency of the test or (b) remove it from the test set and replace with a reasonable alternative, if possible.

Error

slurmstepd: error: Detected 1 oom-kill event(s) in StepId=37205392.0. 
Some of your processes may have been killed by the cgroup out-of-memory handler.
srun: error: node107: task 0: Out Of Memory