Initial commit of SVN repo

A single one-time commit of all existing code was used rather than
trying to convert the SVN repo into Git format.   It was decided that
the commit history (~350 commits) would not be needed going forward.
Corrected calculation of Np

Np was mistakenly calculated as Nx^3, rather than Nx*Ny*Nz.  I wanted to
use this small change to also test GitHub.
Initial attempt at custom shaped networks

The plan is to allow users to generate networks of any shape using the
image analysis tool of their choice (i.e. Matlab), then import these
into PNM.  This commit contains the initial code base for translating
images to the OpenPNM list-adjacency format.
Update to get_neighbor_pores

This changes get_neighbor_pores to return a numpy array rather than a
python list.
Removing generated visualization files from repo
Changed GenericGenerator to no longer call "return self._net" in the generator step, instead requiring a netowork object to be assigned explicity with the get_net function
Removing my (jgostick) personal script file from the repo
Some changes to the CustomGenerator module, as discussed during teleconference on August 15, 2013.
This is a test of the git-flow feature branch functionality
Update get_neighbor_throats to return an ndarray rather than a list when flatten if False
Cleanup of GenericNetwork:  added flatten functionality to several methods, expanded doc strings
Enabled 2D images as input in CustomGenerator
Recommit of my script file
Initial attempt to create a physics module
Update of script file to work with branch
Deleting some generated image files
Updated docstring for the file (mostly to diagnose/solve a git branch/merge problem)
Updated doc string (to test git functions)
Revert "Updated doc string (to test git functions)"

This reverts commit 16cd18a561410cd7774818aa2ee0f21b00fc33ff.
Revert "Updated docstring for the file (mostly to diagnose/solve a git branch/merge problem)"

This reverts commit d7dd338a1e36a9e06224c224e3a892a05e453bd3.