Fix for bug #10144: "set editable" on a disabled particle system

could cause crashes.
Fix related to bug #10198: particle mode didn't respect undo steps
set to 0.

Also made the memory statistics print (ctrl+alt+shift+q) use the
more human readable form to give an overview, instead of printing
out a python script.

source/blender/src/buttons_object.c

@@ -3130,9 +3130,13 @@ void do_effects_panels(unsigned short event)
 				}
 			}
 			else {
-				psys->flag |= PSYS_EDITED;
-				if(G.f & G_PARTICLEEDIT)
-					PE_create_particle_edit(ob, psys);
+				if(psys_check_enabled(ob, psys)) {
+					psys->flag |= PSYS_EDITED;
+					if(G.f & G_PARTICLEEDIT)
+						PE_create_particle_edit(ob, psys);
+				}
+				else
+					error("Particle system not enabled, skipping set editable");
 			}
 		}
 	case B_FIELD_DEP:

source/blender/src/drawobject.c

@@ -3474,6 +3474,8 @@ static void draw_particle_edit(Object *ob, ParticleSystem *psys)
 		PE_hide_keys_time(psys,CFRA);
 		psys_cache_paths(ob,psys,CFRA,0);
 	}
+	if(psys->pathcache==0)
+		return;
 
 	if(pset->flag & PE_SHOW_CHILD && psys->part->draw_as == PART_DRAW_PATH) {
 		if(psys->childcache==0)

source/blender/src/editscreen.c

@@ -1396,7 +1396,7 @@ void screenmain(void)
 		else if (event==QKEY) {
 			/* Temp place to print mem debugging info ctrl+alt+shift + qkey */
 			if ( G.qual == (LR_SHIFTKEY | LR_ALTKEY | LR_CTRLKEY) ) {
-				MEM_printmemlist_pydict();
+				MEM_printmemlist_stats();
 			}
 			
 			else if((G.obedit && G.obedit->type==OB_FONT && g_activearea->spacetype==SPACE_VIEW3D)||g_activearea->spacetype==SPACE_TEXT||g_activearea->spacetype==SPACE_SCRIPT);

source/blender/src/space.c

@@ -1005,6 +1005,8 @@ void BIF_undo_push(char *str)
 			undo_push_armature(str);
 	}
 	else if(G.f & G_PARTICLEEDIT) {
+		if (U.undosteps == 0) return;
+
 		PE_undo_push(str);
 	}
 	else {