"SocketGroup" now supports the letter A for Abyss sockets, and D for Delve sockets.
Abyss (A) and Delve (D) sockets should not be grouped in multiples (for example 'SocketGroup "RGBA"' or 'SocketGroup "DD"', as Abyss and Delve sockets are never linked).
Will also need to add support for them in the item rendering code.