Catch :undefined_variable thrown when Future Parser is enabled with 3.7.x
Remove windows from ensure_package and ensure_resource testing
Fix breaking out of .each loop

And some other small formatting fixes that don't belong in this patch.
Merge pull request #357 from hunner/hasInterfaceWithLookupBug

(PUP-3597) Catch :undefined_variable when Future Parser is enabled on 3.7.x