TST: Stop ignoring warnings in pep8.
TST: Stop ignoring warnings in pep8.

Somehow ignoring warnings makes it raise errors that shouldn't be
according to newer PEP8 versions. For instance, it'd complain when
using 2**4.

johnchase/scikit-bio,johnchase/scikit-bio,jairideout/scikit-bio,kdmurray91/scikit-bio,wdwvt1/scikit-bio,averagehat/scikit-bio,Kleptobismol/scikit-bio,Jorge-C/bipy,averagehat/scikit-bio,Kleptobismol/scikit-bio,xguse/scikit-bio,corburn/scikit-bio,gregcaporaso/scikit-bio,jairideout/scikit-bio,colinbrislawn/scikit-bio,demis001/scikit-bio,jensreeder/scikit-bio,xguse/scikit-bio,Achuth17/scikit-bio,Kleptobismol/scikit-bio,wdwvt1/scikit-bio,corburn/scikit-bio,anderspitman/scikit-bio,jdrudolph/scikit-bio,colinbrislawn/scikit-bio,SamStudio8/scikit-bio,kdmurray91/scikit-bio,anderspitman/scikit-bio,jdrudolph/scikit-bio,SamStudio8/scikit-bio,demis001/scikit-bio,Achuth17/scikit-bio,jensreeder/scikit-bio,gregcaporaso/scikit-bio