Bernard Pull-ard

Tell me if this is the right direction for NeuroUnit.  I added Capabilities and Tests.  I also added Functions, which are glue that Tests can use, or that modelers can use to extract or transform parts of the data prior to testing.  The Neuroconstruct file contains a model class that will eventually know how to run and get data from Neuroconstruct.  Right now it isn't clear to me how you run a model just one time with one simulator in Neuroconstruct, and the code for getting the Vm trace is pretty opaque to, so I'll ask Padraig to tell me how to do that.  Then the NeuroConstruct model class in NeuroUnit will be able to do those things.