feature request: evaluate radius around object to be swapped

[agris-codes]

Not sure if this is still in development or not, but a feature request if it is. When performing a standard swap, let us provide optional arguments for:

1. A specified radius [RAD] around base object to be swapped that looks for another specified object [RADOBJ], which may or may not be a list
2. The ability to condition the swap on [RADOBJ] being within [RAD], or not, with the standard chances applying after that condition is met.

For example origBaseID|swapBaseID|transformOverrides|chance|[RADOBJ([RAD], inclusive)]
So swapBase replaces origBase with vanilla transforms and chances only when ("inclusive") origBase is within [RAD] of [RADOBJ]. And [RADOBJ] can be singular, or a list.

This lets you do some pretty sophisticated swaps, like swapping unlit versions of objects for lit version while rejecting the swap ("exclusive") if a another lit version or manually placed light is detected close to the origBase.