From Alja.

EveTrackPropagator.cxx, TEveTrackPropagator.h:
Bug fix in track propagation in non-constant magnetic field.
Introduce maximum allowed step size.

tutorials/eve/track.C
Change macro to compare Helix and Runge Kutta stepper for 
different types of magnetic field.


git-svn-id: http://root.cern.ch/svn/root/trunk@27119 27541ba8-7e3a-0410-8455-c3a389f83636