Enter(), Entered(), Exit() and Exited() all passed the old loc forward, but everything except a single a case cared about the direction of the movement more than about the specific source.
Since moving multi-tile objects will have multiple sources of movement but a single direction, this change makes it easier to track their movement.
Cleaned up a lot of code around and made proc inputs compatible.
I'll add opacity support for multi-tile objects in a different PR after this is merged, as this has grown large enough and I don't want to compromise the reviewability.
Tested this locally and as expected it didn't impair movement nor produced any runtimes.
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