DOC: Some docstring corrections in scipy.signal
DOC: fix indentation in cumfreq docstring
DOC: Copy-edit and fix layout of the Returns section of the docstring for bayes_mvs
DOC: Reformat the description of the 'zero_method' argument of the 'wilcoxon' function.
Merge pull request #434 from WarrenWeckesser/doc-fix

DOC: An assortment of docstring corrections (mostly restructured text layout corrections)