fix degrees char formatting in man page

fixes issue vmatare#64, thanks to @mariobl for the patch.

fix watchdog ping

Commit #d395107 didn't fix the whole issue, we also need to subtract the
sleeptime now instead of adding it. Otherwise we'd always ping the
watchdog sleeptime seconds too late.
Thanks to github user @susanwl for spotting this.

config: properly disable YAML

yamlconfig.h include was unguarded. Fixes issue vmatare#54.

Fix SimpleLevelParser with string level

Simple fan level entries weren't correctly parsed when the fan level was
enclosed in double quotes, e.g. as in "level full-speed".

remove NEWS from CMakeList.txt

documentation cleanup

output fan lvl string on write error