fixes #3600 Replace / in bookmark name with _

Fix for #3600.  When a user creates a bookmark name that has a "/", it breaks the bookmarks page.  The user would then have to delete the entry manually from the database.  This fixes that be replacing "/" in a bookmark name with "_".  

Not sure if you'd prefer to error out and tell the user not to use "/"'s instead.  Maybe that's the better solution.