Documentation incomplete: stdin is never mentioned

[danr]

The documentation in README.md and in the manpage does not explain that the contents of the bar is populated via stdin.

Examples are also missing. Simple example to get one going like these would be helpful:

while true; do date; done | lemonbar

cat /etc/hostname | lemonbar -p

[LemonBoy]

I guess the README.pod could use some love, feel free to add a INPUT section with a few words about picking the input from stdin and send a PR :)

[aeosynth]

an example of font format would be nice as well, since the xft format can't be used