bump version to 1.6.0

NEWS

+Knot DNS 1.6.0 (2014-10-23)
+===========================
+
+Bugfixes:
+---------
+ - Fix zone expiration when AXFR/IXFR is being refused by master
+ - Fix forced zone refresh on slave (knotc refresh -f)
+
 Knot DNS 1.6.0-rc2 (2014-10-17)
 ===============================
 

configure.ac

 #                                               -*- Autoconf -*-
 
 AC_PREREQ([2.60])
-AC_INIT([knot], [1.6.0-rc2], [knot-dns@labs.nic.cz])
+AC_INIT([knot], [1.6.0], [knot-dns@labs.nic.cz])
 AM_INIT_AUTOMAKE([gnits subdir-objects dist-xz -Wall -Werror])
 AM_SILENT_RULES([yes])
 AC_CONFIG_SRCDIR([src/knot/main.c])