Three streamline changes:
(1) Christoph told me what the tolerances mean, so I modified QvisStreamlinePlotWindow to reflect how they are used.
(2) The core code for doing particle advection has a test to see if the velocity is zero and stop advection (this is an oversimplification).  This behavior is not correct for the new pathline code ... a region could have zero velocity when a particle is there, but it might start moving afterwards.  I removed the test in the case of pathlines.
(3) I added two new warnings: (1) stiffness and (2) critical points.  It looks like we sometimes wrap around critical points without terminating.  This was being reported as "you hit the num steps condition", but is actual separate.  So the critical points warning reflects that.  As far as stiffness, this refers to numerical problems.  Very troublingly, the stiff criteria appears to come up a lot.  I left the warning in, but we'll need to figure out what is going on soon.  (Both warnings can be disabled.)



git-svn-id: http://visit.ilight.com/svn/visit/trunk/src@13192 18c085ea-50e0-402c-830e-de6fd14e8384