UTF-8 BOM's at the start of an ESI-object.

Notice that the removal only happens if the file is actually ESI
processed on delivery, so to get BOM removal for non-XML files,
you may have to disable the XML test and insert a dummy ESI directive
such as <esi:remove>BOMs Be Gone!<esi:remove/> or similar.

Fixes   #1355

If the short description of a log record contains the string
"(unused)" it will not be listed in the documentation.

Format the long log record descriptions for use with pre-formatted
text style.

The xid field is not present in ReqEnd any more, as it is not needed
now that the vxid is used as the record ID. Remove it from the
description.

This patch generates an rst file containing the record tag
documentation from the corresponding header tables.

It also adds a man-page from the vsl.rst document and includes the tag
descriptions.

The old list of tags in varnishlog.rst is removed.

Fixes: #1338

Thanks scoof

instead of the number of incomplete transactions.

Session grouping mode could grab an unintended amount of memory
because the transaction limit was counted towards the incomplete
rather that not yet reported transactions. A long lasting session
would only count as 1 towards the limit even if it had thousands of
complete children that should put it above the limit.

VSL_Dispatch would return with (1) when the cursor reports more data
available, causing the processing of ready transaction not to be
run. Would cause 'varnishlog -d' not to report any data in some
situations.

Add some comments about the different return points in VSL_Dispatch.

If this option is set, the cursor will return EOF when reaching the log tail.

evaluation.

Some options were defined in the incorrect file. Move them where they
should be.

Now EXP_Rearm() can take the timers to change.

Close a race where we could have an object be both born and killed
in the same slot on the inbox.

Also don't flush on SIGINT exit

If the option isn't set, batch records are never returned from the cursor.

If the option is set, batch records are reported, and the next call to
the cursor will return the first record after the batch. Calling
application will then need to know how to use VSL_NEXT pointer macros
to extract the records in the batch.

Change VSLQ_Dispatch to always return after processing one record or
one batch of records. It will return 1 if it should be called again
without sleeping.

This fixes the situation where a calling program is lagging behind,
and VSLQ_Dispatch never returns because there is a constant stream of
new log records.

connection.

Highlights:

* Improved buffer handling. A vtx can now have a mix of buffered and
  shm chunks. And as shm refs are used and later buffered, they can be
  reused on the same vtx. This benefits long running transactions.

* Synth records are now returned by the cursor at the position the
  cursor was at when it was created. This solves a problem when
  writing to a file and a vtx times out, the reading of that file
  would also cause a time out delay.

* Begin records are now strictly honored, and any records before a
  Begin record are now ignored.

* More asserts on the structures

* More comments, should be easier to understand now

* Various other changes