Updated moretrees, plantlife, and added biome_lib

- Solves #204
 - Updated world.mt
 - Updated news.txt

mods/plantlife_modpack/bushes/depends.txt

@@ -1,2 +1,2 @@
 default
-plants_lib
+biome_lib

mods/plantlife_modpack/bushes/init.lua

@@ -194,7 +194,7 @@ abstract_bushes.grow_bush_node = function(pos,dir, leaf_type)
 end
 
 
-plantslib:register_generate_plant({
+biome_lib:register_generate_plant({
     surface = {
 		"default:dirt_with_grass",
 		"stoneage:grass_with_silex",
@@ -240,7 +240,7 @@ abstract_bushes.grow_youngtree_node2 = function(pos, height)
 end
 
 
-plantslib:register_generate_plant({
+biome_lib:register_generate_plant({
     surface = {
 		"default:dirt_with_grass",
 		"stoneage:grass_with_silex",