Update README.md

Fix brand image address of chrome store.
Update bower.json
Update package.json
Move index.html's localtion, Upate Gruntfile.js for debug in the browser
Add jshint and reformat some files
Add test
Add .travis.yml
Add 'npm test' to package.json
Update .travis.yml
Update karma browser from Chrome to PhantomJS
Update README.md
Merge pull request #6 from importre/develop

Add grunt tasks (jshint, watch and debug) and test code