Added Np and Nt @property methods to GenericGeometry
Updated the __repr__ method in base...I was getting tired of the objects subclassed from dict spewing out all their data on the command line.  Now all object print their basic info when you enter >>>pn
Updated many docstrings in GenericNetwork
Added two new methods to GenericNetwork: 'fluids()' and 'geometries()'.  These work similar to the props and labels methods=:
- If no arguments are given, it returns a list geometry or fluid objects associated with the network.
- If a 'name' is given, it returns a handle to the object with that supplied name