Load floating bar JavaScript in <head> using standard WP script queueing

This proposed change loads the floating bar JavaScript using wp_enqueue_scripts(). This has two benefits:
1) It keeps the JavaScript from embedding in the HTML body (messy)
2) It improves compatibility with WordPress minifiers (such as BWP_Minify) that use the list of scripts passed to that function.

With this change, my digg-digg JavaScript can now be automatically minified and concatenated with the rest of my JS to help speed up my site load times.