Cleaned up Tom's docstrings and comments in Delaunay
Adjusted the 'props' method to work when some 'labels' are generated by 'models'.
Note: You can do pn.props(model='models' or mode='constants') to list which pores are generated and which are constant, BUT this does not work with labels, since mode is already taken by the 'set theory' logic to apply
Added 'reduce_coordination' model to the Network.models.pore_coordination' file
NOTE: This is the first 'model' that returns a 'label' array.  It's a perfect example of a Network model...it returns a list of which throats should be deleted to reduce coordination to specified z.  It should be regenerated whenever some other topology manipulations occurs (like a merge or extend) to ensure that z is still correct.