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/weapons/ranged/magic_bows.rb

@@ -0,0 +1,8 @@
+create_projectile_type :msb, start_height: 41, end_height: 37, delay: 31, speed: 3, slope: 15, radius: 8
+
+create_weapon :magic_shortbow do
+  set_special_attack speed: 3, range: 7, energy_requirement: 60, animation: 1074, graphic: { id: 256, height: 100 } do
+    range_damage! projectile: 249, projectile_type: PROJECTILE_TYPES[:msb]
+    range_damage! projectile: 249, projectile_type: PROJECTILE_TYPES[:msb], projectile_graphic: 256, delay: 1
+  end
+end