Update default user agent to Tor Browser Bundle's current string.
Add '--what-country' option for the geographically illiterate.

 * Adds option '-w' or '--what-country to see a country's name and then
   exit. For the times when you do "blockfinder -4 <some IP address>" and you
   still have no clue what country it's in.
Merge pull request #59 from isislovecruft/develop

Add --what-country option.