This adds an experimental option to choose a chip from flashrom's list
using our own heuristics. If successful this should become the default
behaviour when when "-c" is not specified.

Basically this should completely replace the documentation section
"flashrom chip config" at some point.

Adresses issue #26

flashrom might do it anyways, but we have the read image and can
make sure the user didn't by accident provide the other image, for
example.