Try importing the config.py rather than execing

This let's us pass information to the config module, such as the
name hivemind was invoked as.

Change-Id: I7d98bcec569e031a9e9701659c606421be1b455f
Fix matching defaults with args in @configurable

Change-Id: I596a1fdc8bd024941cdca797d6bd72727c1fdad4
Merge "Fix matching defaults with args in @configurable"
Merge "Try importing the config.py rather than execing"