monoblue: show relative age of bookmarks In b24e5a708fad, age calculation was made dynamic (i.e. in javascript), but for some reason bookmarkentry template in monoblue/map got a wrong class. It resulted in /summary and /bookmarks pages always showing exact dates for bookmarks, no age calculation was performed. Let's fix this by using "age" class that is already used in branchentry and tagentry templates in the same map file. As usual, the exact date for such elements is still available in title attribute, so it shows in a tooltip on hover.