Added support for multiple inputs to callbacks for 'onStart', 'onDrag', 'onDrop', etc.

I added support for adding multiple inputs to the callbacks for 'onStart', 'onStop', 'onDrag', 'onOver', 'onOut', and 'onDrop' - if a plain text string is used as the current implementation has it, then it will default to the current behavior.

Here is an example:

__HTML__

    <div data-drag="true" jqyoui-draggable="{onDrag:'dragCallback(\'Hello\', \'World\')}" data-jqyoui-options></div>

__JS__

    function exampleController($scope) {
        $scope.dragCallback = function (event, ui, str1, str2) {
            console.log(str1 + ' ' + str2);
        };
    }

I currently have valid character inputs as all lower and upper case characters, ', _, ., $, whitespace, and open and closed regular & curly brackets.

This feature does not add support for using parentheses inside this callback.