Half wall construction will now build a half wall rather than a full wall. This resolves an "infinite wood" issue.
Deconstructing a half wall will now actually deconstruct the half wall, returning the materials and deleting the entity. Previously it would return the materials and leave the entity in place.
Wood wall frame is now actually de-constructable. Previously it required the frame to be un-anchored, which was impossible.
Description
fixes #525