add support for probes

- ref #17
- target ensemble sends messages to the probe
- probe sends all recoded data to the administrator at the end of the simulation
- client code needs to access recorded probe data from the network for spike
no-synchro communication for probes

- ref #17
- ref #32
Revert "HACK: add actual output comparisons"

This reverts commit d4496b3527cdec0a309d009d5e1f7e54ab5c897f.

Conflicts:
	test/nengo_tests/test_array.py
fix bugs introduced in revert
remove old way of extracting ensemble origin data

- ref #17
- use just probes to collect ensemble origin data
- keep the old interface for client accessing of probe data
- probe objects keep a reference to network and get data from it when requested
remove plotting from test files

- ref #17
- comment out plotting code
- pring out all probe data in test_array for testing
- fix the order of theano function and non-theano code for the probe
remove unused legacy code

- ref #17
- clecn up probes network code
- add print for the second probe in basalganglia
Merge remote-tracking branch 'origin/probes'