Use root relative imports, not file or directory relative imports.

[jamessynge]

Per our discussion, we will use imports starting with pocs or peas, and will import packages and modules but not variables, classes and functions. For example:

import pocs
from pocs.utils import images

To avoid destroying our productivity, we should do this incrementally, perhaps as we modify files. In a while, we can go back and fix missed files.

[jamessynge]

We should start with modifying CONTRIBUTING.md to describe this.

[wtgee]

#252 took care of most of these so I'm closing this issue. While we want to remain vigilant about making sure we do this going forward I'm not sure I want the Issue hanging around. Closing for now.