Update wheezy-stage2

I've never proposed a file change in a repo that wasn't my own.  So if my change seems awful to you, I totally accept your judgement.

My changes to config.txt may be overkill, and in hindsight, I should have looked at the eLinux doc earlier, but I thought it might be helpful to put that info at the top of config.txt and to give users a hint that some settings may impact other settings and features.

Thanks