Make all depends optional except default (#8)

Registers flowerpots based on mods that are enabled and supported.

init.lua

@@ -173,8 +173,8 @@ minetest.register_craft({
 	}
 })
 
--- default farming nodes
 for _, node in pairs({
+	-- default nodes
 	"default:acacia_bush_sapling",
 	"default:acacia_bush_stem",
 	"default:acacia_sapling",
@@ -206,6 +206,7 @@ for _, node in pairs({
 	"default:fern_1",
 	"default:fern_2",
 	"default:fern_3",
+	-- farming nodes
 	"farming:cotton_1",
 	"farming:cotton_2",
 	"farming:cotton_3",
@@ -222,6 +223,7 @@ for _, node in pairs({
 	"farming:wheat_6",
 	"farming:wheat_7",
 	"farming:wheat_8",
+	-- flowers nodes
 	"flowers:dandelion_white",
 	"flowers:dandelion_yellow",
 	"flowers:geranium",
@@ -232,6 +234,7 @@ for _, node in pairs({
 	"flowers:viola",
 	"flowers:chrysanthemum_green",
 	"flowers:tulip_black",
+	-- moretrees nodes
 	"moretrees:beech_sapling",
 	"moretrees:apple_tree_sapling",
 	"moretrees:oak_sapling",
@@ -260,6 +263,7 @@ for _, node in pairs({
 	"moretrees:rubber_tree_sapling_ongen",
 	"moretrees:fir_sapling_ongen",
 	"moretrees:jungletree_sapling_ongen",
+	-- dryplants nodes
 	"dryplants:grass",
 	"dryplants:grass_short",
 	"dryplants:hay",
@@ -273,10 +277,13 @@ for _, node in pairs({
 	"dryplants:reedmace",
 	"dryplants:reedmace_bottom",
 	"dryplants:reedmace_sapling",
+	-- poisonivy nodes
 	"poisonivy:seedling",
 	"poisonivy:sproutling",
 	"poisonivy:climbing",
 
 }) do
+	if minetest.registered_nodes[node] then
 		flowerpot.register_node(node)
 	end
+end

mod.conf

@@ -1,4 +1,4 @@
 name = flowerpot
-depends = default, farming, flowers
-optional_depends = moretrees, dryplants, poisonivy
+depends = default
+optional_depends = moretrees, dryplants, poisonivy, farming, flowers
 description = A stylish flowerpot that can contain most plants.