new function object_is_libdata - checks ob->id.lib but also accounts for proxy's.

Object panels were using object_data_is_libdata, which meant linked obdata could not have object settings changed.

curve2tree 
- option to face leaves up or down
- random pitch and roll options
- place 2 leaves on a point for denser leaves
- random seed entry so you can get reproducible results

source/blender/src/editobject.c

@@ -5484,6 +5484,18 @@ void hookmenu(void)
 	}	
 }
 
+/*
+ * Returns true if the Object is a from an external blend file (libdata)
+ */
+int object_is_libdata(Object *ob)
+{
+	if (!ob) return 0;
+	if (ob->proxy) return 0;
+	if (ob->id.lib) return 1;
+	return 0;
+}
+
+
 /*
  * Returns true if the Object data is a from an external blend file (libdata)
  */