Build Modifier - Add "Reversed" Option

This commit introduces the ability to make the Build Modifier operate in reverse,
essentially allowing it to be used as a "deconstruction" effect.

(See D219 for more details about use cases for this)

release/scripts/startup/bl_ui/properties_data_modifier.py

@@ -160,6 +160,7 @@ class DATA_PT_modifiers(ModifierButtonsPanel, Panel):
         col = split.column()
         col.prop(md, "frame_start")
         col.prop(md, "frame_duration")
+        col.prop(md, "use_reverse")
 
         col = split.column()
         col.prop(md, "use_random_order")