Bitcore v0.8 release

Release date: 17 December 2014

Github Milestone: https://github.com/bitpay/bitcore/milestones/v0.8

Design Discussion: https://docs.google.com/a/bitpay.com/document/d/1i8jcArLX4ZB5D08zmaJsQe5reP207bcXf2X5VP8nIkQ/edit

v0.8.1 release