MAINT: resolve pyflake F403	'from module import *' used

* For external modules, resolve imported members
* Most internal relative modules were ignored or marked noqa: F403
* Convert a few internal absolute imports to relative imports

As numpy is Python 3 only, these import statements are now unnecessary
and don't alter runtime behavior.

Run the 2to3 ws_comma fixer on *.py files. Some lines are now too long
and will need to be broken at some point. OTOH, some lines were already
too long and need to be broken at some point. Now seems as good a time
as any to do this with open PRs at a minimum.

The logging message in numpy.distutils.log.set_threshold
mispelled threshold.