Add ranged combat support

* Clean up the CombatAction and Attack code to make it easier to use for
  range.

* Add collision detection to the distance checks before attacking in the
  CombatAction.

* Create a Ruby DSL for defining projectile types and fix the
  ProjectileUpdateOperation so it uses the correct position offset.

* Fix the packet structure of the HintIconMessageEncoder.

data/plugins/combat/combat_style.rb

@@ -0,0 +1,11 @@
+class CombatStyle
+  attr_reader :button, :config, :attack_type, :block_animation
+  attr_accessor :attack
+
+  def initialize(button, config, attack_type, block_animation)
+    @button          = button
+    @config          = config
+    @attack_type     = attack_type
+    @block_animation = block_animation
+  end
+end