refactor event plot into reusable basemap/scatter plot routine (for
inventory plots)
Merge remote-tracking branch 'upstream/master' into event_plot_refactor
just warn on missing basemap (to make rest of imaging test suite run properly)
renaming imaging.basemap to imaging.maps
Catalog.plot(): `show` and `outfile` options
Catalog.plot(): adjust axes limits and title placement
Catalog.plot(): add image tests
Catalog.plot(): more examples in API docs
install basemap in travis for image tests
Merge pull request #753 from megies/event_plot_refactor

Catalog.plot() refactoring
fix one catalog plot image test