Duel / PVP invitation

New function for PVP / Duel invitation.

If one wants to PVP another, they can type /pvp *name*  , it will send an invitation to the person ( just like trade rep ) with a 30seconds agree or disagree. The person have to be online.
It will also be transmitted to Global chat in different color (Neon Orange) accepted or declined. 

Once accepted, both parties will be summoned into Arena in 1minute with a tab to click Ready for battle.

Once both parties are ready, count down will start in 10seconds.
And the battle begins.

Maybe there can be a new achievement
Duel battles 100 victory
Duel battles 700 victory (special hero cape dye non-tradeable) since its announced in global, don't think there will be laming of special cape.

Duel results can be on helbreath.net under stats - duels. It will be permanent. So laming will not go unsuspected.

There could be additional 2 NPC (ELV/ARES) in the Arena to "stake" the fight.
Both parties have to put items or coins to the NPC and to be accepted by both parties.
Winners will receive their winnings via mail.