Add bonemealing callback to melons.

* Adds a _mcl_on_bonemealing callback to the unripe melon plants.

mods/ITEMS/mcl_farming/melon.lua

@@ -109,6 +109,12 @@ for s=1,7 do
 		groups = {dig_immediate=3, not_in_creative_inventory=1, plant=1,attached_node=1, dig_by_water=1,destroy_by_lava_flow=1, plant_melon_stem=s},
 		sounds = mcl_sounds.node_sound_leaves_defaults(),
 		_mcl_blast_resistance = 0,
+		_mcl_on_bonemealing = function(pointed_thing, placer)
+			local pos = pointed_thing.under
+			local n = minetest.get_node(pos)
+			local stages = math.random(2, 5)
+			return mcl_farming:grow_plant("plant_melon_stem", pos, n, stages, true)
+		end
 	})
 end