Flake8 omero/util

This PR fixes the flake8 warnings from `omero/util`

One external file has been moved untouched to `omero_ext`. Three files have been removed, these are all: unimported by anything and: have no main method, are clearly old or are clearly broken.

Travis and Jenkins should both pass.


`flake8` barfs at the `self`. I think I just set the debug level to reflect the comment.