Added some grunt tasks

I added some grunt tasks for increase efficiency of development. Accordingly, I added some scaffold and moved old files to new directory as src. Below are the details of the features.

:cow: Grunt tasks:
+ `$ grunt`: default command that are `build`, `server` and `watch`.
+ `$ grunt test`: Run `jshint` on `src/js/*.js`.
+ `$ grunt build`:  Run `test` task and copy src files to dest.
+ `$ grunt server`: Start connect server and open URL on browser.
+ `$ grunt watch`: Watch src files and do `build` task.
+ `$ grunt deploy`: deploy dest files to `gh-pages` branch.