Fetches the binding table for the gpd-root combination. We use the link value `SYSTEM:Binding_Tables' in the root object, `root', history node to hold an association list of gpd-bt pairs. The binding table for a given gpd-root combination is thus obtained by scanning the link value `SYSTEM:Binding_Tables' for root, searching (every odd position) for the occurance of the gpd label, and picking the next label as the binding table.
If the search fails, a new object is created for binding table `bt', and a gpd-bt association is made in the `root' history node. In this case, the history node is also stored after the linking is made. The association is made using unbound `gpd' and `bt' labels.
The parameters are:
Function returns: