removed useless worldfiles and fixed a couple of outdated settings

Author: rtv

worlds/SFU.world

@@ -10,7 +10,7 @@ speedup -1 # as fast as possible
 
 paused 0
 resolution 0.05
-threads 0
+threads 4
 
 # configure the GUI window
 window

worlds/asr.world

@@ -136,7 +136,7 @@ trickedoutpioneer
 define silly position ( 	
   size [1.000 1.000 0.500]
   fiducial_return 22
-  laser_return 2
+  ranger_return 2
   gui_outline 1
   gripper_return 1
 )