[feature/fix] add listen command for upstream pub

Add a listen command to get access to the event stream of the upstream
pub/sub API.

This patch gives back access from the command line to the power
information of a container, including filtering the event stream to only
have events relevent to this container.

This changes the workflow a little bit for users, but should result in a
cleaner access to profiling data in the future.

Related to #18.
2 jobs for process-management in 1 minute and 6 seconds
Status Job ID Name Coverage
  Test
passed #14686
rapl
py.test

00:00:40

 
  Style
passed #14687
flake8

00:00:26