More on display list state tracking

• Upon glCallList, the Tilesort SPU needs to update its state records (one master record plus one per server) to reflect the state changes contained in a display list. If you don't, you'll often get incorrect renderings.

• Requires keeping a private copy of the display list.

• Suppose the list contains 1000's of glVertex commands and just one glEnable. We really only need to save the glEnable call. But we don't currently do that.

• Changing the Tilesort SPU's GL dispatch table is pretty inefficient too. Need to do so for each glCallList.