open links inside messages in new tabs/windows

i often find myself following links from the logs, then closing the tab, then realizing later that i lost my log tab. it hurts a bit more now due to the realtime websocket support (so cool!), so i figured this might be warranted.

i haven't actually tested this, i just blindly added target="_blank" to the subset of links that looked appropriate. feel free to modify or throw away entirely! it was a trivial change, so a PR seemed a bit nicer than an issue. :P