Replace "About" page by a refreshed FAQ

This pull request can be previewed live here:
http://bitcoinfaq.us.to/en/faq

A FAQ or "Common myths" page has been asked a while ago.

I've reworked the most relevant parts of the existing press FAQ and Wiki FAQ/Myths and tried to keep the best arguments in a concice and objective way.

Some of these questions are controversial and there is a lot of texts. A good review will be useful for accuracy, potential ambiguous assertions, unrelevant texts, incorrect english and typos.

This pull request also refresh the press FAQ and allows the FAQ to be translated.