Add thousand seperator for jquery.numeric.js

Add thousand separator for Integer part of inputted number.
decimal part won't format with ',' separator.

* @name     numeric
* @param    config      { decimal : "." , negative : true , separator : "," }
* @param    callback     A function that runs if the number is not valid (fires onblur)

* @example  $(".numeric").numeric();
* @example  $(".numeric").numeric({ separator : "," }); // use , as separator
* @example  $(".numeric").numeric({ decimal : "." , separator : "," }); // use , as separator
* @example  $(".numeric").numeric({ negative : false , separator : "," }); // do not allow negative values