DC: performance: pipe all through one shell

decreases calls to SU drastically as we collect the commands and once done,
we trigger it all through one shell.
thanks to roottools we reuse our opened shells for that task.

also since we have otto all goes more fluent as well, stuttering decreased,
all seems to be more smooth.
thats why i made use of otto at the cpu monitor as well.

Change-Id: Ida1dc220f02127dbe731080ee070e656e3294ca8