Implemented Hell Deaths

1. New files:
a) /objects/gates_to_hell.lua
b) /entities/grimreaper.lua

2. app.lua:
Modified afterLoad() so that the gates_to_hell object will be added to a world's objects list when its loaded from an old saved game.

3. die.lua:
a) Modified action_die_start() so that males can either go to heaven or hell.
b) +action_die_tick_reaper: Makes hell deaths happen.

4. humanoid.lua:
a) Modefiend the die_anims() setting function to make it support the rise_hell_east animation.
b) Modified Humanoid_startAction(): So that grim reapers with no actions will have the idle action be their default action.

5. patient.lua:
a) +rise_hell_east death animation.
b) Modified afterLoad() to give patients the rise_hell_east animation when they don't have it.

6. world.lua:
a) +newObjectType(): I've created this function so that app.lua can use it to add the new gates_to_hell object to old worlds.
b) Modified objectPlaced() by adding statements to make it respond to the spawning of lava holes.