First port of Bio.NMR docstrings to numpy-like sphinx-ready markup

This is a test to see how the change in format of the documentation looks like. I added an example to the classes in xpktools, which uncovered a bug in  Peaktools.__init__. I don't want to over-step my bounds, but I fixed this, and generally tidied the code up, by adding spaces around variable assignments, bringing code separated by a semi-colon down into two lines, and other such simple things. It seems useful to make such changes when they are obvious, but I am not sure how to proceed. If I didn't fix little bugs, adding things like example code in the docstrings (which can be run as docstring tests during sphinx compilation) wouldn't be possible. I can go the route of adding a bug, and then being assigned it, if that would be more appropriate. I'm just excited to be of help.