[#1697] Simplify _is_test() a bit
[#1697] Remove ckanext/resourceproxy/tests/test_proxy.py from blacklist

It's passing now.
[#1697] Fix PEP8's E303 on ckanext/resourceproxy/tests/test_proxy.py
Merge branch '1697-dont-validate-e501-on-tests'
Merge branch 'master' into 1725-extend-datastore