The actual contents of the input ROM binary files and the contents of the
created arrays are unchanged.
Multiple ROM image include files can be included in the same source module
without the need for any #undef BOOT_CODE_SIZE, etc.
This change lays the groundwork for adding support for Rev 3 3B2 models,
which includes the Model 500, Model 600, and Model 1000.
Rather than use the fixed strings "400" and "1000" in file names, the
strings "rev2" and "rev3" will be used, which allows greater flexibility
to implement various system configurations more easily.
Additionally, this change adds a copy of the Debug Monitor (DEMON) ROM
image for the Rev 2 board, to be used soon in a later checkin.
