Irdeto code clean up: Rename some variables, rewrite camkey algorithm, and remove support of older obsoleted card (CAID 0662, 1702, and 1762).

I have cleaned up a lot of code spaghetti on reader-irdeto.c particularly on those obsoleted CAID 0662, 1702, and 1762. I hope that this won't break anything but I'm not quite certain. @OptimumPower @WXbet I know that you guys have Irdeto cards. Can you guys verify that it is still working with your Irdeto cards like before?

Thanks in advance.