Add Random PNM example using Delaunay and Voronoi
Added the ability to have units on arrays.  Both pint and quantities append a units attribute that was being lost during conversion to a pure sp.array.
- removed header from docs
- updated info in docs (like copyright date)
IP now stores current saturation level as self.sat. Updated at end of run() or update_results().
Removed unit fiddling...I will move this into a feature branch
Added ability to reorder models.  This addresses issue #226.  Also update the GenericPhase init to use this rather than directly tinkering with the _models dict as it was doing.
Added an 'ideal_mixture' model the misc Phases models.  This calculates the mole fraction weighted average property of a mixture from the pure component values
Added the ability to stitch two networks together.  This uses Delaunay tessellation and requires the networks be positioned corrrectly in space first.
- The method is underscored since it will surely evolve under development
Added the ability to send a list of labels to apply to new pores when 'extending' the network
Bug fix in stitch, the shape of the adjacency matrix was count wrong
Adjusted 'stitch' to accept a list of pores to stitch rather than two labels.  Also added the existing labels in the doner network to the recipient's labels by default, and 'stitched' to the new throats generated by the method.
Added options to 'stitch'
- now user can specifiy delaunay or nearest for connection (not much difference)
- can also specify the maximum allowed throat length...this is a very useful improvement
Updates to the 'stitch' method
- It now adds the donor network labels correctly
- It labels stitch throats as just 'stitched' and nothing else
- Also change the default labels in _get_indicies to 'all', from no default
Forgot to add **kwargs to Phase.models.misc.ideal_mixture
Improved the check_geometry_health and check_physics_health methods to also check throats not just pores
Fixed 'pretty printing' of labels.  It didn't print nice when the whole list was requested.
Fixed bug #230...the throat indices in the physics models were incorrect
interpolate_data did not like it when it was called by a user customized class (my_phases.air).  The check to determine the type of the calling class is now more robust.  I wonder if this bug will appear anywhere else?
Ooops, forgot to change one line in hydraulic_conductance when fixing #230
Generalized Amalgamate data to work on custom objects (not OpenPNM objects)