output buffer is full.

This isn't needed since we no longer use VRE_NOTEMPTY_ATSTART

This reverts commit 43b009a8.

transferring huge amounts of data, and it should not be used that
way.

But we have commands like ban.list which potentially can return at
metric shitload of data and this is a problem.

This commit implements a cli_limit paramter which (with its upper
limit) protects from responses that cannot be moved by the CLI
protocol no matter what.

We set the default to a low 4096 bytes, in order to make people
specifically shoot their feet off if they really want to see 200k
bans.

Yes, I should have done this five years ago...

Move vparam.h to mgt/mgt_param.h

it will be used from.

which just hangs if we don't have it

Reduce scope of heritage.h
Reduce scope of libvcl.h

Fixes #1042

Conflicts:

	bin/varnishd/mgt/mgt_param.c

it belongs there.

params much clearer.  Manager should never read the childs copy.