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, incorrect english and typos.

This pull request also refresh the press FAQ and allows the FAQ to be translated.