All of my latest hell deaths code excluding my graphics code changes

Changes I've made since Mark copied my old code into his repository:

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.