lang: add a constant for the translation path

gamecore/lang.lua

@@ -24,6 +24,8 @@
 
 local LanguageManager = Object:extend()
 
+local TRANSLATION_PATH = "datas/languages/"
+
 -- INIT FUNCTIONS
 -- Initialize and configure the translation system
 
@@ -42,11 +44,11 @@ end
 -- Get informations from the translation manager
 
 function LanguageManager:getTranslationData()
-  local _path = "datas/languages/init.lua"
+  local _path = TRANSLATION_PATH .. "init.lua"
   local fileinfo = love.filesystem.getInfo(_path)
 
   if fileinfo ~= nil then
-    self.datas = require "datas.languages"
+    self.datas = require(TRANSLATION_PATH)
   else
     self.datas = nil
   end