Draft: Add XOffset and YOffset SPRTINFO parameters

Currently does not function as intended. This used to be the SF_ODDCENTER merge request, and the intended behavior is to be able to allow you to set extra subpixel offsets, as seen in the gif below.

This Lua script is supposed to apply offsets to nearly all of Sonic's sprites, but it fails to process the parameters at all and spits out a Lua error. skins.sprinfo has been expose to allow this Lua script to function, but appears to not at the moment.

This wad also similarly contains a SPRTINFO lump that does not function.