Better remote handling support for Parsley

Refer [Issue 293](https://github.com/guillaumepotier/Parsley.js/issues/293).

Major changes.
1. Form validate method now returns a promise.
2. Remote validator returns a promise

Minor changes
1. Fixed some typos.

Overall, the changes are pretty minor but the single breaking change will be a pain if not duly informed.

Example of using the new syntax

```
    <!-- HTML -->
    <input type="text" name="nickname" data-required="true" data-remote="http://linkToServerMethod" data-remote-method="POST" />

    // JavaScript
    var validateForm = form.parsley("validate");
    validateForm.then(
        function(){
            // Do on success
        },
        function(){
            // Do on failure/error/invalid
        }
    )

```