tests: add test for continuation lines with comments
ratelimit: fix off-by-one

The current code might make sense during startup for service restart
limiting:
With burst=1 after starting num is 1, so the next ('first') restart is
still accepted ( 1 <= 1). However, once interval has expired, num is 1
after the first restart, so the second restart is also accepted.

This change is also useful in combination with watchdogs:
With burst=1 and a very large interval the system can be restarted on
the first failure.
test-udev: include missing.h

We need MS_REC and MS_SHARED defined for a proper compilation, so get them from
'missing.h' if not defined already.
man: Write man page for systemd-bootchart(1)

Mostly coppied from bootchart.conf(5)
man: Make options consistent

Option listings seemed to be pretty much random, some were short opt,
long opt, others were long opt, short opt. This just makes every option
with a short and long opt that I could find in the order short opt, long
opt, for formatting's sake.