FR: Show performance meter with double click on 'CPU/RAM usage' in TCP

[pcp]

Currently, clicking or double clicking on the 'CPU/RAM Usage' readout at the bottom of the TCP does nothing.

Most times I want to pull up the performance meter, that's where my attention is.

Would be a nice little touch if double-clicking it could show/hide the more detailed stats.

Also it'd be awesome to see total latency here, although I guess that's a separate FR.