Add ability to reinitialize

[kevinchappell]

By popular demand, formBuilder can now be reinitialized by calling it again.

$('.fb-textarea').formBuilder();

Then later:

var opts = {
              messages: {
                text: 'Cool Input'
              }
            };
$('.fb-textarea').formBuilder(opts);

The second call can be made from an ajax or button click callback. With these options, when formBuilder rerenders the default label for text input will change from "Text field" to "Cool Input".

[yichingwu]

I found there are still some items can't be translated.

[kevinchappell]

@wudoz Fixed in #96