Force usage of internal cue sheet

[siebenstreich]

If both internal and external cue sheet are present, I don't see a way how to force the internal one being used.

I think there should be a way to achieve that. Either an additional command line option. Or maybe it would make sense to use the internal over the external one by default (since it is "closer" at the source file). The usage of the external one could then be forced by the -cue command line option.