Prepare for 5.1.0 final

configure.ac

 AC_PREREQ(2.59)
 AC_COPYRIGHT([Copyright (c) 2006 Verdens Gang AS
-Copyright (c) 2006-2016 Varnish Software])
+Copyright (c) 2006-2017 Varnish Software])
 AC_REVISION([$Id$])
-AC_INIT([Varnish], [trunk], [varnish-dev@varnish-cache.org])
+AC_INIT([Varnish], [5.1.0], [varnish-dev@varnish-cache.org])
 AC_CONFIG_SRCDIR(include/miniobj.h)
 AC_CONFIG_HEADERS([config.h])
 AC_CONFIG_MACRO_DIR([m4])

doc/changes.rst

 ================================
-Varnish Cache 5.1.0 (unreleased)
+Varnish Cache 5.1.0 (2017-03-15)
 ================================
 
 * Added varnishd command-line options -I, -x and -?, and tightened

include/vrt.h

@@ -39,7 +39,7 @@
  * binary/load-time compatible, increment MAJOR version
  *
  *
- * 6.0 (unreleased):
+ * 6.0 (2017-03-15):
  *	VRT_hit_for_pass added
  *	VRT_ipcmp added
  *	VRT_Vmod_Init signature changed