Revert "Temporary commit b/c this network sux"

This reverts commit 266c11c7811d9ab9f8003a1178f7060dd5ba5f3d.
Add an option to automatically choose an address from 192.168.1.0/24.

Refactor things a bit too, and  beef up the pydoc somewhat.
Factor IP address space management into sts/util. Add convenience option to
specify prefix as /32.
More descriptive error message
Set netns's IP address properly, and generally clean up code.
Allow controllers to be launched in a network namespace