ULE/yielding patch for testing.

[martinko]

Garrett Cooper wrote:
> 
>    No matter what OS you have, if a website's slow (and it's not because 
> you don't have OpenGL support in your X-server), slowness will remain 
> constant. It's just the way unfortunately that browsers are designed.
> 

Not always true.  For instance zooming (with mouse scroll) on this site 
<mapy.cz> is significantly slower on FreeBSD than on Windows (using the 
latest SeaMonkey in both cases).  Of course, I do not blame FreeBSD, it 
likely is fault of SeaMonkey in this case.