Add installation info on README
Add installation info on README

Make users know that taggle.js is available on Bower and NPM.
omichelsen/taggle.js,okcoker/taggle.js,okcoker/taggle.js,omichelsen/taggle.js,jimf/taggle.js,okcoker/taggle.js,jimf/taggle.js,omichelsen/taggle.js