Don't mix const and non-const pointers. This should make jenkins happy again.
If workspace_thread is not be big enough to hold all the objcore pointers
that need to be purged we iterate until done.

Fixes #1551

Conflicts:
	bin/varnishd/cache/cache_hash.c
Ensure that we never call a VDP with a zero length unless we are done.

Fixes #1561
Make a dedicated cleanup function for req->vary_? to match the
dedicated setup function we have.

Fixes	#1553
Prepare for 4.0.2-rc1 release.
Prevent a segfault on varnish reconnect in the varnishstat hitrate
implementation
Add list of changes.
Remove incorrect changelog entry.

After re-reading the patch, this isn't important enough to
warrant a changelog entry.

Spotted by: 	fgsch
Update copyright statement.
Unhide vcl.show from 'help' output, it was hidden due to overzealous
copy&paste.

Spotted by:	scn
varnishlog -k argument

Implement -k argument in vut for use with varnishlog. This takes as an
argument the number of log transactions to be processed before
exiting. Useful to stop varnishlog after a given set of log data has
been produced.

Drop -s from the 'not implemented yet' list as this option has very
limited usefullness.