Added tests for config file reading and caching.
Added a first image comparison test.

This required some boilerplate code.
Added an example project for testing.
New example project fixture.

Used by the py.test runner to provide a fresh project for every test.
Also added a test for the event handling.
Added show_plot kwargs to some plotting commands.

Useful to capture the figure to disc and testing.
Adding test for multiple event plotting.
Adding waveform and station data to example project.
New test for event information retrieval.
Added test for the waveform cache usage.