3376 with inconsistencies on bookmark back buttons

http://code.google.com/p/otwarchive/issues/detail?id=3376

When saving or editing a bookmark, there is a button called "Back to Bookmarks" that takes you to your bookmarks. It should just say My Bookmarks so you know where it leads. ("Back" suggests a return to where you came from, which would be the work. "Bookmarks" without "My" could mean the bookmarks for the work or the bookmarks for that fandom or the main bookmarks index.)  Also, there should be an h2 on the show bookmarks page and the button should be at the top, not the bottom. Since users who don't own the bookmark can view the bookmark page if they're clever, they get a button that says "Bookmarks by %{bookmarker}" instead.