Link neuronal population (V2A) to ephys and behavior --POC--

New request by the user for the NIH meeting

the concept is to link one neuronal population to other data types, electrophysiology and behavior. The concept is that the user right clicks on any one neuron of one population (V2A) and a drop down menu appears with two options 1) see electrophysiological data; 2) see behavioural data. The user click on either one of them, and the tab on the right (where the 2D viewer is) opens either on the corresponding tab (either electrophysiology (this one already exists) or Behavioural data (this one needs to be created)) and shows the content. At this time the content will be a PDF (coming from the client soon).

cc @zsinnema