complete summary from py_wind, + significant changes to reading and writing scripts

This change does the following:

* Creation of new function and corresponding py_wind option. typing 1 creates a onefile summary of most of the useful physical quantites in the wind and saves it as root.complete so one can easily access quantites in the wind with the astropy.io.ascii routines.

* python routines py_read_output.py, py_plot_output.py and py_plot_util.py have been significantly revamped. 

* for how to use consult instructions here: https://github.com/agnwinds/python/wiki/Useful-python-commands-for-reading-and-processing-outputs 

Please try these instructions out @Higginbottom @kslong @smangham at your leisure and let me know if you spot any broken code or shortcomings.

Nick, feel free to start adding your own generally useful scripts to py_progs- I suppose we should try and use the routines I've written for reading in files at least, but you may want to use your own plotting routines, for example.

I don't think any of this work needs to be done with any urgency but we can just gradually work on the scripts and plotting as we work towards a public release.