added notice about the new clipboard feature in the gulp file to the README file
added notice about the new clipboard feature in the gulp file to the README file

shadesoflight/tumblr-template-sass,chadfurman/tumblr-template-sass,shadesoflight/tumblr-template-sass,ShadeLotus/tumblr-template-sass,chadfurman/tumblr-template-sass,ShadeLotus/tumblr-template-sass