Some fixes to topotools.py, adjusted plotting so pcolor and imshow pixels are centered on x,y of topo, added test data and plotting of Kahului Harbor
Merge branch 'master' into topotools_fix_xyz

Some additional fixes added to topotools beyond PR#90 that was just merged.

* master:
fixed docstring in test_plot_kahului
Fixed Topography.read when argument is a URL, deprecated get_topo function and added improved version fetch_topo_url that is now used by read.  Added a unit test.
Fixed new unit test for fetch_topo_url to delete metadata file
Do not set .z attribute of Topograophy class unless its an unstructured grid
Moved and renamed tests/test_topotools.py (and data file).  Need to see if Travis works ok.
Changed tests to get Travis to work(?)...
Take out plot tests and add main program to run these outside of nose.
Print directory and files to try to debug kahului file not found.
Travis fails for fetch_topo_url example so remove 'test' from the name of this test
test travis for plotting by adding apt-get install python-matplotlib to .travis.yml
trying pip install matplotlib in .travis.yml
use Agg matplotlib backend for tests
retest fetching url and remove test of plotting until clawpack/clawpack is updated so travis gets recent changes to visclaw (need add_colormaps)
debugging travis with nosetests -s
cd to geoclaw/tests in travis: will all our tests be here?
change tests so nosetests can be run from top level directory
use mirrors in pip install, following clawpack/.travis.yml
cleaned up plotting tests, fix axes
Merged changes to topotools.py from PR#87 into other recent changes to this file. Plan to close that PR.
Merge pull request #96 from rjleveque/topotools_fix_xyz

Topotools fix and Kahului harbor plot