Only resume proctable refreshes if started
Stop background updates if window is not shown (bgo#309839)

If the window is minimized, stop background data collection
to minimize wakeups. On window restore/focus, start it again.
https://bugzilla.gnome.org/show_bug.cgi?id=309839
Merge branch 'wip/idleproctable' with various fixes to reduce number of
wakeups.
Removed forgotten debug log