WIP Ensemble refactor.
Allow filters with varying widths.

Used in receiving values for PES, for example.
Generate filter regions from dicts or lists of pairs.
Factor eval_points grabbing for reduced connections.
WIP PES for Ensembles.
flake8 and docstring.
Further tests for LIF ensemble.
Final tests for LIF assembly.
Merge branch 'new_pacman2' into new_pacman2_simulator