Get rid of trailing whitespace.

Commit generated by command:

find -type f ! -path '*.git*' ! -path '*.png' ! -path '*.ico' ! -path \
    '*.ogg' | xargs -I '{}' sed -i '{}' -e 's/\t*$//g' -e 's/ *$//g'

modules/game_skills/skills.lua

@@ -233,7 +233,7 @@ end
 function checkExpSpeed()
   local player = g_game.getLocalPlayer()
   if not player then return end
-  
+
   local currentExp = player:getExperience()
   local currentTime = g_clock.seconds()
   if player.lastExps ~= nil then