Added information about locale on readme

[adrianotadao]

What

Added information about internationalization. #87

[elmoaaron]

I thinks its a great information for the readme.

[adrianotadao]

@bokmann hey David, could you please take a look here?

[gr8bit]

I think you should also be able to include the specific languages you require. "locale-all" will build all languages into the javascript... Am I right? If so, do you think we should mention that as well?

[adrianotadao]

@gr8bit I agree with you, do you mean to describe when the user needs to use like the doc?

<script src='fullcalendar/locale/es.js'></script>
<script>

  $(function() {

    $('#calendar').fullCalendar({
    });

  });

</script>

I need to test if this is working and then, I can add this ...