2.5: Various

* Weight paint: brush strength was changed to both define weight
  and strength, this can't work, made them separate buttons.
* Allow adding particle system as modifier (fix crash).
* 3D view modal ops (zoom ..) could not be ended when invoked
  from a button.
* Fix some warnings.
* Fix spelling in particle RNA property.

source/blender/editors/transform/transform_input.c

@@ -270,7 +270,7 @@ void initMouseInputMode(TransInfo *t, MouseInput *mi, MouseInputMode mode)
 		break;
 	case INPUT_TRACKBALL:
 		/* factor has to become setting or so */
-		mi->factor = 0.02f;
+		mi->factor = 0.01f;
 		mi->apply = InputTrackBall;
 		t->helpline = HLP_TRACKBALL;
 		break;