merged:
   https://github.com/doughiebert/ruby-portaudio/commit/7e4606515c19416bd567c8554d9c5377c3b1dd88
   https://github.com/doughiebert/ruby-portaudio/commit/ae7e48314fd7f43880d06114546678feabbbe21f
   https://github.com/doughiebert/ruby-portaudio/commit/2605f07e418bcaf37a1ba2a903e357f71d41eee9
added:
   [] operator for hosts and some bounds checking for it
   me(darkscout) and doughiebert to README

fixed:
   DeviceCollection.each