Each format should use different JS handle to prevent caching

[mnelson4]

Caching plugins sometimes use the "handle" used for wp_enqueue_script as a key for their cache. So when our epub and PDF formats both use the handle "pmb_js" or whatever it is, we get the wrong JS loading on the print page.
To prevent this, each format's JS handle should be different.
I'll also need to update the custom designs I've done for clients though to use these new script handles.