PEP8: Remove trailing whitespaces
refs #644
PEP8: E101 indentation contains mixed spaces and tabs
refs #644
PEP8: E225 missing whitespace around operator
refs #644
PEP8: E221 multiple spaces before operator
refs #644
PEP8: E231 missing whitespace
refs #644
Merge master into pep8
Merge branch 'master' into pep8