partitioning patch

[trudheim]

What would you like to be added:
You said the partitioning needed to be more dynamic, so here is a stab at it. It builds images with the defined sizes.
What I could not get to work was predefined UUIDs for the partitions. So there is something up with the '-u' option for the various make_ scripts in builder. I have not investigated it closer.
Also, there is no error checking in this patch, it is more a proof of concept, and for that, it will do.

Why is this needed:
Images may need to be smaller or larger depending on the usecase.

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patch.zip