Added ability to do leaf decay on default trees, moved several configuration

settings into a separate file.  You should disable leaf decay in minetest_game
if you enable it here.

settings.lua

@@ -0,0 +1,33 @@
+-- Configuration variables
+
+-- Enable replacement of default trees with birch if you want but be warned -
+-- due to bugs in the speed of the engine's map generator/loader, doing so\
+-- will slow it WAY down.
+
+moretrees.enable_replace_default_trees = false
+
+-- Enable the first one if you want this mod's leafdecay code to affect the 
+-- old default trees.  You'll want to manually disable the default leafdecay
+-- code in minetest_game if you enable this.
+
+moretrees.enable_default_leafdecay = false
+
+-- various settings to configure leaf decay in general.
+
+moretrees.leafdecay_delay = 2
+moretrees.leafdecay_chance = 150
+moretrees.leafdecay_radius = 5
+
+moretrees.palm_leafdecay_radius = 8
+
+moretrees.default_leafdecay_delay = 2
+moretrees.default_leafdecay_chance = 50
+moretrees.default_leafdecay_radius = 4
+
+-- Change these settings if you want default trees to be gradually cut down
+-- above the elevation where firs normally generate.
+
+moretrees.firs_remove_default_trees = false
+moretrees.firs_remove_interval = 2
+moretrees.firs_remove_chance = 150
+