Pass in project directory when tasks module contains explicit namespace. #243
When a `tasks.py` module contains an explict Collection (named either `ns` or `namespace`), the parent directory (used to find the project-specific configuration file (e.g. `invoke.yaml`) is not passed in to the Collection created from the factory method `Collection.from_module`. This caused the file to not be found except when explicitly specified with the -f flag. Compare to the similar Collection() invocation about 12 lines below this change. Fix #234.
I'm happy to add a test for this, but I'm not sure the best place to, since it relies on having both tasks.py and invoke.yaml in the same directory. Trying to solve this is what led me down the path to #240, but I don't think there's a good unit test for this problem. An integration test, perhaps?