Preliminary testing of the strokes framework

[David REVOY]

Oh good for the system monitor if it makes the work less.
> Is this slowdown noticeable while painting?
Yes, on master it's almost smooth , and your branch its slow. The test 
here is on a more than 9000px wide picture, using a big airbrush on the 
top to paint (from my old preset 
http://david.revoy.free.fr/forums/krita/2011-05-28_krita-preset_deevad.zip  
).

Don't hesitate to ask if you wish I run a specific test for you with my 
computer. Just explain/write how to do it as for a n00b :D