Fixed buff duration check, fixed group buffs

- The duration needed to be set on the buff object "before "the buff is
actually added.  Because of this, I made the distinction between setup(0
(setting up the buff object) and add() (adding the buff stats to the
player).

- Group buffs would add the buff based on each individual player's
skillmods instead of the buffer's.  Due to this, I made a "buffer"
parameter for doAddBuff().  If there is a buffer, regardless of it's a
buffer within our group, we can specify them, otherwise provide null.

src/services/GroupService.java

@@ -188,8 +188,7 @@ public class GroupService implements INetworkDispatch {
 			if(otherMember != member) {
 				for(Buff buff : ((CreatureObject) otherMember).getBuffList().get()) {
 					if(buff.isGroupBuff()) {
-						Buff newBuff = core.buffService.doAddBuff(member, buff.getBuffName());
-						newBuff.setGroupBufferId(buff.getGroupBufferId());
+						core.buffService.doAddBuff(member, buff.getBuffName(), (CreatureObject) core.objectService.getObject(buff.getGroupBufferId()));
 					}
 				}
 				return;