Add a link to the varnishlog man page and the logging chapter in the tutorial

remove -i and -I, add -m and describe it. Simplify the docs. The user only needs to care about -m, really

I'm not sure if we should go into more detail about how the whole thing works

Fixes #1062

of maintaining magic hex-bit values that must match.

Fixes #1042

Use a mark&mark strategy to test all obj.* bans even if there are
req.* bans in the way.