Made it "functional"

Came across this while searching for something in the mod section of the forum.

Couldn't resist to update this:

Goals of this change:

* Only count actually playing users for the limit before it was taking all players (including spectators, rr players) into account
* Added the Notification that informs players about the limit.

Please read the comments in the code for more details ;)
Merge pull request #1 from GhoulofGSG9/patch-1

Make it "functional"
Many Thanks Ghoul!