Update for compatibility with Varnish 6.0.

Also update the compatibility statement for RE2 -- compatible up
to and including 2018-04-01.

And use $Synopsis manual in the documentation -- we write our own
SYNOPSIS.

configure.ac

 AC_PREREQ([2.68])
-AC_INIT([libvmod-re2], [trunk], [varnish-support@uplex.de], [vmod-re2])
+AC_INIT([libvmod-re2], [1.4.4], [varnish-support@uplex.de], [vmod-re2])
 AC_COPYRIGHT([Copyright 2016-2017 UPLEX - Nils Goroll Systemoptimierung])
 AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_AUX_DIR([build-aux])
@@ -39,7 +39,7 @@ if echo "$RE2_LIBS" | grep -- '-L' >/dev/null ; then
 	fi
 fi
 
-VARNISH_PREREQ([master])
+VARNISH_PREREQ([6.0.0])
 VARNISH_VMODS([re2])
 
 VMOD_TESTS="$(cd $srcdir/src && echo tests/*.vtc)"

src/vmod_re2.vcc

 #-
-# Copyright (c) 2016-2017 UPLEX Nils Goroll Systemoptimierung
+# Copyright (c) 2016-2018 UPLEX Nils Goroll Systemoptimierung
 # All rights reserved
 #
 # Author: Geoffrey Simmons <geoffrey.simmons@uplex.de>
@@ -9,8 +9,15 @@
 
 $Module re2 3 Varnish Module for access to the Google RE2 regular expression engine
 
+$Synopsis manual
+
+SYNOPSIS
+========
+
 ::
 
+  import re2;
+
   # regex object interface
   new OBJECT = re2.regex(STRING pattern [, <regex options>])
   BOOL <obj>.match(STRING)
@@ -1185,13 +1192,12 @@ Example::
 REQUIREMENTS
 ============
 
-The VMOD requires the Varnish master branch, and is not compatible
-with any current released versions of Varnish. See the source
+The VMOD requires Varnish since version 6.0.0. See the source
 repository for versions of the VMOD that are compatible with other
 Varnish versions.
 
 It requires the RE2 library, and has been tested against RE2 versions
-2015-06-01 through 2017-11-01.
+2015-06-01 through 2018-04-01.
 
 INSTALLATION
 ============