This adds a new system definition that, when selected, causes some
pre-processing to be done on VICE CRT (cartridge) files. These have
multiple chunks representing potentially overlapping ROM regions.
Also, pulled RawData.cs from CiderPress2, as it has some newer stuff
that we want. (It would've been handy for the OMF code.)
Also, renamed SystemDefs.cs to SystemDef.cs to match the class name.
(issue #183)
