Blender Git Loki

Small particle effectors update:
* Greetings from farsthary: particle rotation is now taken into account for particle effector direction.
** This gives all kinds of new possibilities as he shows in his blog http://farsthary.wordpress.com/2011/02/08/vortex-particle-simple-tut/.
**The only modification I made to his patch was to use the actual rotated particle direction as the effector direction as this defaults to the particle velocity vector, so no actual new options are needed.
* I also added an "effector amount" setting for particle effectors so that only a part of the particles can be considered as effectors. This makes it possible to create simple "farsthary vortexes" with only one particle system.
* Also some tiny reorganization of the falloff min/max values for a nicer ui.