Big cleanup and todo

[emolch]

Mopad in its present form is not very useful as a Python module and many things could be improved. Here just a few suggestions in random order:

• the BeachBall methods ploBB(), save_BB(), pa_plot, full_shere_plot() should be renamed into a consistent naming scheme

• these methods take kwargs not **kwargs, why? This is not very intuitiv to use (and the documentation of the method is even wrong):

   beach.save_BB(dict(plot_outfile='mopad.png', plot_outfile_format='png'))
  

• the string/value hybrid behaviour of the getter functions in MomentTensor should be avoided

• exceptions raiseid in the code should contain proper information about what has gone wrong

• error messages should never be printed to stdout

• remove print statements in the getter functions of MomentTensor (this should be fixed quickly, because, whoever sees this will never again want to have a single look at mopad).

• is there any good reason for using realpath() and abspath() when dealing with filenames in this code?

• many of the excessive if-elif-else-orgies could be replaced with simple dict mappings. This would heavily shorten the code.