Add tags and an question/answers divider.

- Also tweak some of the styling.
- The post header need some styling, it feels boring in and closed in its
current dark grey. Would like some colour. We will probably need to have it in
a few different colors (question, locked question, answer, accepted answer,
down-voted-into-oblivion answer).
- I do not like the red of the vote down button. Actually, I'm not all that
fond of the voting buttons at all to be honest.
- Thinking about changing the color scheme of the navigation bar, something a
bit more fun than the default blue?
- Maybe we could have the voting stuff by tapping the score?

Signed-off-by: Aron Cedercrantz <aron@cedercrantz.se>