ENH: filepaths accepted as args for pwmantel
TST/DOC: added test for pwmantel and modified changelog and documentation
TST/DOC: added test data for pwmantel test and modified changelog
DOC: updated documentation and modified changelog
TST/DOC: added test data for pwmantel test and modified changelog and docs
DOC: modified changelog
DOC: modified changelog
DOC: modified docs for pep8
Merge pull request #794 from shiffer1/issue-792

Issue 792