Update README.md

Fixed typo in readme:

$('#my-form').trigger('checkForm.areYouSure');

should be:

$('#my-form').trigger('checkform.areYouSure');
Merge pull request #36 from Scadoodles/patch-1

Update README.md
Merge branch 'master' into 1.7-dev
Prevent multiple prompts in IE/Chrome

* IE (and now Chrome) raise multiple onbeforeunload events when a link
is clicked. We use a timer to prevent multiple submits.

* Cleaned up the field selector.  Now that we work on all input types,
broden the match out.