Adding unique ID to frontend inline styles

[dcooney]

This PR adds a unique style ID to the inline styles output.

<style id="ub-styles">...</style>

This is useful for Ajax plugins such as Ajax Load More to be able to pull in custom styles for the post when loading content async.

Note: Looks like my editor formatted the entire init.php file removing empty line ending where the only code addition is on line 1010. Let me know if you'd like me to reformat this.