Allows placement of a font size controller within your blog. By default its placed in your sidebar and footer
By placing [fontcontroller] or by using [fontcontroller=small] (for large or small) This shortcode is also searched for in the footer.php and header.php template files
By putting in (this will check if the function exists or not first as well)
Yes, but there is no worry, performance wise jQuery is almost always loaded anyway so you shouldn't see any performance changes.