Rewrite audio handling to be a unified system

[ForLoveOfCats]

Maybe integrate with entity system? Definitely add echo and reverb depending on surroundings.

[ForLoveOfCats]

The existing audio stuff has not been modified to use the new entity system and could still cause errors. TODO

[ForLoveOfCats]

This has been started but I'm not going to do it all at once, I have other things to work on (world save, water, ect)

Sfx moved to the new system:

• BUTTON_MOUSEOVER
• ITEM_PICKUP

Sfx left to move to the new system:

• HITSOUND
• KILLSOUND
• THUNDERBOLT_FIRE
• SCATTERSHOCK_FIRE
• ROCKET_JUMPER_FIRE
• ROCKET_JUMPER_EXPLODE
• ITEM_THROW
• PLAYER_LAND