Fix the support of mapped IPv4 addresses.
Thanks to Mark Bonnekessel and Markus Boese for making me aware of the
problems.
MFC after: 1 week
Count consecutive read requests as blocking in CTL for files and ZVOLs.

Technically read requests can be executed in any order or simultaneously
since they are not changing any data.  But ZFS prefetcher goes crasy when
it receives consecutive requests from different threads.  Since prefetcher
works on level of separate blocks, instead of two consecutive 128K requests
it may receive 32 8K requests in mixed order.

This patch is more workaround then a real fix, and it does not fix all of
prefetcher problems, but it improves sequential read speed by 3-4x times
in some configurations.  On the other side it may hurt performance if
some backing store has no prefetch, that is why it is disabled by default
for raw devices.

MFC after:	2 weeks
Add mentor information for kami a.k.a. me.

My mentors are cs and koobs.

Differential Revision:	https://reviews.freebsd.org/D975
Reviewed by:	cs
Approved by:	cs
add some missing mentor->mentee relationship
Update to reflect the current members of portmgr
Add myself as a ports committer, mentored by bapt/bdrewery.
Fix rendering
Include the received chunk padding when reporting an unknown chunk.
MFC after: 1 week