* Refactors all plane parts to use a common helper for
calculating connections to adjacent planes.
Also fixes problems with updating these connections on neighbor updates.
* Fix conflicting GuiSync ID.
* Slightly refactor PlaneConnectionHelper, and fix an issue where the bounding box was calculated incorrectly by using the wrong up-direction.
Replaced fuzzy ints with a well defined enum
Moved API related cell interfaces to a new subpackage
Introduced a new client helper method to register a cell texture for a storage channel
Added a method to obtain the storage channel for a drive or chest slot
Added a new cell state for cells with stored items but neither types nor completely full