On the 65816, 16-bit data access instructions (e.g. LDA abs) are
expanded to 24 bits by merging in the Data Bank Register (B). The
value of the register is difficult to determine via static analysis,
so we need a way to annotate the disassembly with the correct value.
Without this, the mapping of address to file offset will sometimes
be incorrect.
This change adds the basic data structures and "fixup" function, a
functional but incomplete editor, and source for a new test case.
