Added a clan-tag indexing to hold any original casesensitive name by a lowercase key.
This does ease up the usage for chatcommands and also the complete administrative functions.
Added a player validation check the loading process:
> When in covalence an User-ID does either not exist, or the id exists but the name is empty, it get excluded from the load-in (= kick^^)
> This is needed to prevent (on veryrare-cases) to have "ghost-players" inside a clan.