[12562] Remove not required duplicate indexes

Signed-off-by: Schmoozerd <schmoozerd@cmangos>
[mr2977] usable code from 12560, 12561, 12566, 12567
[mr2978] Use unified GuidSet for players/active objects in map. avoid using mapReference for player update iterations, must be much more safe (but need make same operations in other places). testing. MUST BE DANGEROWS!
[mr2979] Redesign GridStates operations v0.2

includes squashed commit of the following:

commit adacd2c009fec2cb662a3261de1a462f98724a6c
Author: rsa <kris13@bk.ru>
Date:   Sun Sep 29 13:39:15 2013 +0400

    redesign GridState operations, must solve some problems with grid load/unload part 2 (only code simplify).

commit 1345a833fc243db593546dc91b7452a648d11318
Author: rsa <kris13@bk.ru>
Date:   Sun Sep 29 11:28:29 2013 +0400

    redesign GridState operations, must solve some problems with grid load/unload. testing