Logging off in safe zones

If a player logs off in a safe zone he will lose half his mana and all
buffs. This is to counter trains with pre-buffed characters.
Removed use of oSpell and added note in purge.kod

No longer needed to use oSpell to find and cast purge on the player and
added a note in purge.kod it might break this function.
Merge pull request #105 from broodhill/Patch1

Fix to stop pre-buffed character trains