Update tran.js

1. Language file now loaded through ajax.
2. tran object created and two functions namely translate and populateText have been defined.
3. These changes have been done so that if handlebars( client side templating) is being used, the function translate can be called directly using tran.translate().
Update tran.js

Changes done so that  content comes from english language file if there is no value for key.
Merge pull request #2 from akvgit/master

Update tran.js