Python: scripts should support python build target

[dan-rigdon-bel]

Ironically, the python scripts in the scripts folder - bootstrap.py, setup.py, and build.py - do not yet support Python. This is because of the special need to generate the wheel for pip that is tied to the "other" setup.py script in the root folder of this repository. The setup.py script in the root folder is the "installer" for pypy.

One way we could better support the python target by wrapping them in the scripts would be to generate the (root) setup.py script from the scripts/setup.py script.

[mcneel-build]

Linked with RH3DM-90