add travis-ci build status to README
add travis-ci build status to README

chrismytton/fancybox-rails,chrismytton/fancybox-rails,VoroninNick/eduction-abroad,VoroninNick/eduction-abroad,kyparn/fancybox2-rails,kyparn/fancybox2-rails,escobara/fancybox-rails,varyform/fancybox2-rails,escobara/fancybox-rails,varyform/fancybox2-rails,escobara/fancybox-rails,chrismytton/fancybox-rails,varyform/fancybox2-rails,kyparn/fancybox2-rails