Because enterprises tend to move very slowly, we're keeping Python 2.7 compatibility for RBTools 3.0. Two issues had snuck in that were breaking this: 1. We had renamed uses of `assertRaisesRegexp` to use the new `assertRaisesRegex` name. Unfortunately, this new name is only Python 3.1+. I've changed it back, and made two uses of it instead call the more appropriate `assertRaisesMessage` helper, so now there's only one place that hits it. 2. The `tqdm` library depends on `importlib_resources`. Unfortunately, while tqdm is maintaining Python 2.7 compatibility, the newer versions of its dependency are not. I've added a pin for the last compatible version. Testing Done: Ran setup.py develop under Python 2.7, and then ran all unit tests.