Some patients should go to hell when they die - enter the Grim Reaper!

The pulls below represent all of the hell death code started by Luís Duarte and completed by Joseph Sheppard, excluding his graphics code changes:
(The on_ground animation "missing hat and white shoes" bug fixing graphics
code changes are not included in this commit.)  

These are the commit notes from Joseph

Code Style Changes:
To make my code follow the Corsix code conventions and be more readable
I've made these changes:
1. The variables in my Lua code no longer have CamelCase names instead
they have lower case underscore seperated names.
2. I've split up long lines of code (>80 characters) into multiple
lines, for example: by having function parameters be listed vertically
instead of horizontally.
3. Horizontally listed function parameter are now spaced like this:
(v_one, v_two, v_three)
4.. I've removed some unesscary white spaces
5. I've replaced some tabs I found with spaces
6. I've split single line IF & for statements into multiple line
statements because this increases their glancing readability.

Code Changes:
1. The "alt + s" sound hotkey will now call Audio:soundEffectsOn(state),
turning lava hole sounds off and on accordingly.
2. World:getHellDeathSpawnPoints() now makes sure that the lava hole use
tiles for hell death spawn points being checked won't be in rooms.
3 World:getHellDeathSpawnPoints(): I've replaced the stair case of IF
statements that was in this function with one IF statement which has all
the conditions from the previous IF statements in its IF statement.
4. I've included my idle_spawn persistance fix in this commit despite
having pushed it to the CorsixTH repository in its own pull request
because hell deaths can't be persisted without it.
5. I've removed 3 unnecessary functions:
*World:updateTypeAnimations()
* World:initTypeAnimations()
* World:doesObjectExist()
6. World: setType() is now as it was before it called
World:initTypeAnimations()
7. World:afterLoad() no longer calls World:updateTypeAnimations() for
old saved games.
8. Patient:afterLoad() is now responsible for giving patients from old
saved games the new hell death animations.
9. The saved game version number is now 84 because 83 has been used by
my Chewbacca death fix pull request.

• There are now 3 supported spawn point scenarios:
 1) The original south spawn point scenario which requires lots of south space.
 2) A new south spawn point scenario which can occur in 1 tile wide north-south corridors.
 3) A east spawn point scenario which can occur in 1 tile wide west-east corridors.
 I will add north and west scenarios tomorrow.

• The grim reaper can now use the lava hole's west tile.

• World:getHellDeathSpawnPoints() has become: World:checkHellDeathSpawnPoints(patient, hole_x, hole_y, grim_x, grim_y)

• There's much less code in World:checkHellDeathSpawnPoints() than used to be in World:getHellDeathSpawnPoints()* because lots of duplicated code has been removed and replace with a call to function which checks the usability of lava hole use tiles.

• + World:lavaHoleUseTileUsable(hole_x, hole_y, start_x, start_y, use_tile_x, use_tile_y)

• The spawn points for hell deaths are now determined in the first phase of the hell death die action.

Added north and west hell death spawn point scenarios

NOTE: api version and saved game version may need correcting when being merged