Add rubber tree (FIXME: rubber trees don't generate)

init.lua

@@ -24,6 +24,9 @@ industrialtest={}
 industrialtest.updateDelay=1 -- Note: Make this value smaller to make machines update more frequently (it may make server more laggy)
 industrialtest.developerMode=true -- Enables additional utils useful when developing mod
 
+-- Others
+industrialtest.random=PseudoRandom(os.time())
+
 -- load other lua files
 dofile(modpath.."/compatibility.lua")
 dofile(modpath.."/api.lua")
@@ -35,3 +38,4 @@ if industrialtest.developerMode then
 	dofile(modpath.."/utils.lua")
 end
 dofile(modpath.."/cables.lua")
+dofile(modpath.."/mapgen.lua")