rb_raise calls longjmp, which bypasses C++ destructors, and also keeps the error for catch blocks from being unallocated if passed by reference, which we do for exceptions.
Some of the calls I left can still jump out of try blocks, which you're not supposed to do, but there shouldn't be any objects with destructors initialized at those points so it's probably fine.
- `System.config` has become `CONFIG.to_hash`
- `CONFIG[]` can be used to look up settings
- `CONFIG[]=` can be used to add/change settings
- When reading settings, user settings are preferred over defaults
- Changes are immediately stored in the user settings file