Set 'maxDiff' to 'None' in 'test_output.py'
Move 'self.maxDiff' assignment in 'test_output.py'
Comment out 'test_geojson()' test

Issue ref: #11
Use Python 3.4 for Travis builds

Issue ref: #11
Add external link to docs, reformat section
Add development information to docs
Properly fix bug #7, remove all 'prettying' code

e1fb1318e7b82a257dd1aafde51e4828c16b8d8b got this fix close but
importing the json module was unnecessary, the geojson module can
format the output itself.