Add -Walways to run_tests.sh
Add -Walways to run_tests.sh

This adds the argument `-Walways` to the command in `run_tests.sh`.
Adding this argument makes python 2.7 behave more similarly to
3+ so that it no longer swallows warnings after they have been
shown once.

aleju/ImageAugmenter,aleju/imgaug,aleju/imgaug