Keep snapshots of player stats from the past 5 seconds.

Keep snapshots of player stats from the past 5 seconds.

A snapshot is taken each time one of the player's stats changes, with
changes that occur at the same time (based on GetTime()) collected into
the same snapshot.

OvalePaperDoll.stat is now a pointer to the head of the snapshot queue,
pointing to the most recent snapshot.

git-svn-id: svn://svn.curseforge.net/wow/ovale/mainline/trunk@1006 d5049fe3-3747-40f7-a4b5-f36d6801af5f