We could have done away with it just because the memcell values are always the last parameter. However, this might not always be the case in the future. Also, it's better for consistency reasons.
An undocumented change from the previous commit:
- When the Lua script is not able to find an object, the message is now printed to `errors.txt`, not just to `log.txt`.
- Lua bindings are no longer using FFI in favor of the "classic" Lua C API.
- This makes it work properly on native Linux builds.
- Changed the Lua API slightly:
- Removed the `api.event_preparefunc()` function because it is no longer necessary. Instead, you can pass any function you want without preparing it first.
- Added an `api.event_exists()` function. Takes a single `name` argument.
- Any `api.find_*()` functions return `nil` instead of an userdata representing a null pointer when the requested object is not found.
