ROMset v0.2

When we give an indicaton about the PCB, we also need to point the images to the locations on the PCB. So I'll try this for Extendec Basic at first:

<romset>
  <images>
    <bin id="rom_bank_1" file="exbasc.bin" crc="" sha1="" />
    <bin id="rom_bank_2" file="exbasd.bin" crc="" sha1="" />
    <bin id="grom" file="exbasg.bin" crc="" sha1="" />
  </images>

  <mapping>
    <region type="rom" where="cpu">
       <map id="rom_bank_1" start="0x6000" length="0x2000" />
       <map id="rom_bank_2" start="0x6000" length="0x2000" />
    </region>
    <region type="rom" where="grom" tag="std">  
       <map id="grom" start="0x6000" length="0x8000" />
    </region>
 </mapping>

 <software>
    <system driver="ti99_4a" pcb="rom2bank+grom"/>
    <system driver="ti99_4ae" pcb="rom2bank+grom"/>
    <system driver="ti99_8" pcb="rom2bank+grom"/>

    <item set="exbas" name="Extended Basic" maker="Texas Instruments" year="1981">
       <uses tag="std" />
    </item>
   </software>
</romset>

cpu region is referenced as REGION_CPU1 in the code, grom is REGION_USER1.

Problems:

• system attribute must have multiplicities, so I introduced an element.
• We don't know which ROM is at which bank number.