Advanced log display / filtering

At least explore options.
- [x] What about output where there's no `\n` for a while?
- [ ] How about color-coding output lines by process?
- Tough part is finding a good color palette to use for this
- [ ] Or even syntax highlighting and advanced navigation a 'la http://lnav.org/
- [x] Highlight logs from the same process/fd as the currently hovered one
- [ ] Filter by string / regex
- [x] Click a log category to hide it?
- [x] Shift-click FDs / process names to show logs of only that one
- What should happen when clicking on an FD is not clear (toggle other FDs of this process, or all processes?), so not touching that.
- [x] Click process name to toggle display of all its logs