Health Bar

For craftbukkit 1.5.2, not tested on previous builds!

• Added world disabling for mobs.
  You can see two new nodes in the configs: world-disabling: false, disabled-world: a,b,c.
• Added a node for health below the name: you can now set a proportion (use-proportion: true, proportional-to 10).
  Explaination:
  if you disable the proportion, a player's health will be between 0 and 20 (counting the half hearts) and if a player has a higher health (maybe set by a plugin) will be showed for example as 50.
  If you use the proportion and set the value 100 the health will be a percentage, so players with different max healths but with full health, will have both '100 'under the tag.
  If you set the proportion to 10, you can use the real hearts of the players (0 to 10).