Genie:  Throw EINVAL, not ENOEXEC, for bad offsets
Genie:  Factor out ReadProgramFromDataFork()
Genie:  Read code from data fork if no rsrc fork

Assume the code occupies the whole data fork if the resource fork is empty.
Genie:  Verify 68K binaries

Make sure we don't execute PPC binaries by accident.
Genie:  Read code from data fork if missing rsrc

If the 'cfrg' resource (for PPC) or the code resource (for 68K) is missing,
assume the code occupies the entire data fork.
Merge branch 'allow-code-in-data-fork'