Remove state from graph drivers into new EProjectNetView which holds roots, filter, and session for a EProjectGraph/EProjectWeb instance. Created manager class for retrieving graph/web instances, creating graphs (storing a series of direct relationships and returning the EProjectGraph instance corresponding to the root GAV), and storing loose-leaf sets of relationships. It also handles creation/registration of sessions.

This eliminates the need to interact directly with the graph driver beyond initialization, and moves the session-selection methods out of the graph api proper. Sessions are now better positioned to contain selections/conditions that apply to more than one graph or web.