Prepare for next major release

NEWS

+Knot DNS 2.7.0-dev (2018-xx-xx)
+===============================
+
 Knot DNS 2.6.0 (2017-09-29)
 ===========================
 

configure.ac

@@ -3,9 +3,9 @@
 AC_PREREQ([2.60])
 
 m4_define([knot_VERSION_MAJOR],2)dnl
-m4_define([knot_VERSION_MINOR],6)dnl
+m4_define([knot_VERSION_MINOR],7)dnl
 m4_define([knot_VERSION_PATCH],0)dnl
-m4_define([knot_VERSION_EXTRA],)dnl
+m4_define([knot_VERSION_EXTRA],-dev)dnl
 m4_define([knot_PKG_VERSION],[knot_VERSION_MAJOR.knot_VERSION_MINOR.knot_VERSION_PATCH]knot_VERSION_EXTRA)dnl
 
 AC_INIT([knot], knot_PKG_VERSION, [knot-dns@labs.nic.cz])