[PATCH] flashcp: improve speed & some clean ups

[Frans Meulenbroeks]

@Artem,

Thanks, I will try to do this in smaller chunks. Probably I'll come
with a patch to let the code comply with the coding guidelines first,
then step by step introduce the changes

@Russ,

Thanks for the info. I'll add a warning and make it opt-in.
That way if you know there was no power fail during the erase and you
know what you are doing you can safe some time.

Note that a new patch might take a little while as I am fairly busy
with severa things at the moment.

Best regards, Frans