Changed cmdPrint to cmd.
Removed hash-bang in module files which aren't executed directly,with the exception of topo.py, which I haven't touched.
Comment tweaks and additions.
First crack at restoring mininet python style, assisted by handy'unpep8' script, which does most of the work.
- topo.py is still in pep8- not all examples work, but this is due to other issues
Add static code checking for style and errors
This required a change to logging, which now uses a singleton pattern.
For all future checkins, 'make codecheck' should pass.
Add xterm support