Add Roger Ver to the Press page (fixes #145)

After considering the arguments of everyone, I come to the conclusion that the best decision is to include Roger Ver. Legitimate concerns have been raised and enough good arguments have been made to mitigate these concerns. Roger demonstrated professional skills at making interviews and his dedication to Bitcoin makes no doubt. Additionally, a disclaimer has already been added by Trace Mayer to keep bitcoin.org politically neutral. Accordingly, I am adding Roger Ver to the press center.

In order to have a clearer path toward interviewees selection, I am also suggesting guidelines for inclusion in the README.
https://github.com/bitcoin/bitcoin.org/pull/221