Add new data config key

This release introduce new data config key, enable you to strip the data-formula and data-format attribute out of your html.

For example

<form id="calx">
    <input data-cell="A1">
    <input data-cell="A2">
    <input data-cell="A3">
</form>
<script>
    $('#calx').calx({
        data : {
            A1 : { value : 200 , format : '$ 0,0' },
            A1 : { value : '50%' , format : '0 %' },
            A3 : { formula : 'A1-(A1*A2)' }
        }
    });
</script>