Add Hindi Translation

नमस्ते और आपका स्वागत है! The Hindi translation is being reviewed and is nearly complete. Greetings to over 300 million people who speak Hindi that can now learn more about Bitcoin in their native language.

Thank you very much to all of the translators, reviewers and coordinators that have assisted us with this!

Here's a link to the live preview:
http://bitcoinhi.us.to/hi/