Added 'Bookmark' to Sugarcane/Responsive sidebar

* Since hashchanges have been removed, there's no longer an obvious way
of bookmarking a game state. This link functions identically to Jonah's
- it contains the (otherwise inaccessible) URL hash, which can be used
to re-start the story from that passage.
* Un-minified the CSS of all the targets.
* Added a CSS style for <center> tags in passages.