MNT/TST: removed dumpSWMM from graphics, plotters now just return a Figure, and updated tests
MNT: got rid of all_tests
MNT/TST: now using -six- module to python 2/3 compat
MNT: added exporter to __init__
MNT: updates to travis and notebooks
MNT: add -six- to travis
ENH/TST: create exporter module
MNT: force travis to use mpl1.3.0
Merge pull request #38 from phobson/add-exporter

ENH: Add exporter module