Passive mobs now try to flee from battle.
Implemented changing weapons in battle.

Changes the currently held item, but you lose that turn.
Implemented health bars.

Required the creation of a new packet for sending health information to
the player.
Health bars at 100% health are set to be the width of the entity's name
and are accurate to every 1/10 of maxHealth.
Fixed creepers becoming ghosts after exploding.

If creepers were in battle, you could still hit them after they exploded.
Now they will be properly removed from battle.
Merge branch 'master' into 1.6.2

Conflicts:
	burnedkirby/TurnBasedBattleMod/Battle.java
Fixed/Revamped health display.

Getting health information is different in 1.6.2.
While fixing this, also changed health display.
This change hasn't been fully tested so may not work in multiplayer.