Squashed commit of the following:

commit 774ed203ce7eb47e0f066fb6d7039d252c2dd453
Author: james.knight <james.knight-5@postgrad.manchester.ac.uk>
Date:   Thu Sep 4 15:59:05 2014 +0100

    flake8

commit 89631b670daa61a2bea53b4c418712ef4cc44ffe
Author: james.knight <james.knight-5@postgrad.manchester.ac.uk>
Date:   Thu Sep 4 15:28:53 2014 +0100

    Support for multiple PES learning rules per-ensemble

commit 5b8c8935814d427ba4e7e7159345132d3908400a
Author: james.knight <james.knight-5@postgrad.manchester.ac.uk>
Date:   Thu Sep 4 13:59:50 2014 +0100

    Independant dimensions for individual non-accumulated input filters

commit 599433cbd5351ba8f5f1d249ee056a29f4aee9e6
Author: james.knight <james.knight-5@postgrad.manchester.ac.uk>
Date:   Wed Sep 3 17:04:36 2014 +0100

    Mostly working
    * pes module implements connection transform
    * IntermediateConnection passes through modulatoryness of connection
    * filters associated with modulatory connections aren't merged
    * Ensembles have modulatory filters and PES regions

commit 9c51e4bb516914a73b003c785e9a9b7a9a601bd8
Author: james.knight <james.knight-5@postgrad.manchester.ac.uk>
Date:   Tue Sep 2 14:43:48 2014 +0100

    Merge branch 'origin/jamie_pes'
    Merged c-code from old PES branch - Won't actually work!

    Conflicts:
    	nengo_spinnaker/builder.py
    	nengo_spinnaker/edges.py
    	nengo_spinnaker/ensemble_vertex.py
    	nengo_spinnaker/utils/connections.py
    	nengo_spinnaker/utils/filters.py
    	spinnaker_components/filter/filter_main.c