New Options JqueryUI slider and Switcher

**1. I've added two new options:**
 - JqueryUI slider - http://i.imgur.com/e9Fh5Ar.jpg
 - Switcher - https://github.com/Smartik89


**2. Changed Google Font script totally. Now it is dependend by JQuery, but instead it do his job better:**
 - Add styleshet link in head and remove previously added.
 - Don't embed the link in head if the user has not selected a custom font(if the key is equal with "none" or "Select a font"). This caused a "400 bad request" in previous script.
 - Allow the user to set his custom preview text and text size.

**3. Other small changes and code corections.**


P.S. I've tried to replace old media option with this new available in WP 3.5 but without succes. Please when you have fre time update this option, you know better than us SMOF code. devinsays has this option and for sure you can add it to SMOF.

Best regards and thank you for this awesome framework.

Andrei