Fix for very long filenames (255+ chars) on OS X (HFS+)

I ran into an issue with one particular bookmark that had a title of ~260 characters. Since filenames can't be larger than 255 characters (on HFS+, at least) I just wrote some quick code to cut it off at 248 (that's to leave room for the 7 characters that spell .webloc)
One small request here. Can you add `.strip()` to the end in the event that the last character is a space?