Create an override directory if none exists
Don't verify triggers against the action list

Descended from f1007b50b
Fix documentation errors for ADD_AREA_ITEM.
Also change the function default for container_to_add_to to a safe value.
Dork around with the readme

 - Properly denote function/macro arguments and returns.
 - Clear up some issues (mismatched parentheses, compile warnings, etc.)
 - Delete trailing whitespace, to make the diff interesting.
 - Adjust indentation of verbatim sections to hopefully appear a bit
   more consistent.