Enabled Gemnasium dependency status badge
Removed Gemfile.lock, as this one's really a gem that should be plugged in into other applications. See http://yehudakatz.com/2010/12/16/clarifying-the-roles-of-the-gemspec-and-gemfile/ for more rationale.
Added extended summary & description, fixed dependencies; removed json dep from Gemfile
Pumped up version