add support for direct ensembles and typical connections for these

- able to add direct ensembles to a network
- able to connect direct ensembles with inputs and spiking ensembles
- supports just typical connection i.e. decoder/ encoder connection
- add the basal ganglia example, which contains the model with direct ensembles
- ref #17
change nef library path specification
remove unused ensemble name
Merge remote-tracking branch 'origin/consolidate-step2'

- close #27

Conflicts:
	src/nef_theano/ensemble.py
	src/nef_theano/input.py