Port cogent.draw.distribution_plots.generate_box_plots

Now bipy.draw.distributions.boxplots. The autogenerated docs also include autogenerated boxplots!
Merge branch 'master' into genboxplots

Conflicts:
	doc/source/index.rst
Fill out docstrings a bit more

Also add plot directive instructions to doc guide.
Merge branch 'master' into genboxplots

Conflicts:
	doc/source/index.rst
bipy -> skbio
move draw subpackage under skbio
add ref to scipy's ttest
port generate_comparative_plots

now named grouped_distributions
fix pep8 "fun"
use agg in tests

w0000000000000000000000000000000000000000000000000000000000t
hopefully fix issue with DISPLAY
Merge pull request #149 from ElBrogrammer/genboxplots

Port cogent.draw.distribution_plots.generate_box_plots