[Kst] Performance

[Barth Netterfield]

It seems to me that the order we should be attacking this is:
-Make sure there are no updates or redraws we don't need
-Make sure that anything we do in the updates or redraws that we don't need to 
do isn't done. (eg, don't redraw hidden plots, don't recalculate psds if 
input doesn't change)
-Make sure things aren't waiting for things that they don't need to be waiting 
for...

-Come up with a way of testing for regressions in this.

And then, 

-Improve the algorithms within the updates.