Fix analyzer framerate when mouseover play scrubber

This patch prevents the framerate of all analyzers from
increasing beyond the framerate set in the interface at all times.
It however will allow the analyser to redraw as often as required
to prevent artifacting when the play scrubber is drawn in front.
Formatting
Merge pull request #4313 from TheUbuntuGuy/master

Fix analyzer framerate when mouseover play scrubber.  Fixes ##2504