Updates for release

NEWS

+4.15.6
+======
+- Update configure.ac.in syntax
+- Namespace of the gir needs capital first letter
+- Bump GLib (and gio, gthread, etc) minimum to 2.50.0
+- Remove typedef already defined by G_DECLARE_FINAL_TYPE macro
+  (Fixes #4)
+
+
 4.15.5
 ======
 - Bump Xfce version to 4.16pre2

configure.ac.in

@@ -13,10 +13,10 @@ dnl ***************************
 m4_define([libxfce4util_verinfo], [7:0:0])
 m4_define([libxfce4util_version_major], [4])
 m4_define([libxfce4util_version_minor], [15])
-m4_define([libxfce4util_version_micro], [5])
+m4_define([libxfce4util_version_micro], [6])
 m4_define([libxfce4util_version_nano], [])   dnl leave this empty to have no nano version
 m4_define([libxfce4util_version_build], [@REVISION@])
-m4_define([libxfce4util_version_tag], [git])
+m4_define([libxfce4util_version_tag], [])
 m4_define([libxfce4util_version], [libxfce4util_version_major().libxfce4util_version_minor().libxfce4util_version_micro()ifelse(libxfce4util_version_nano(), [], [], [.libxfce4util_version_nano()])ifelse(libxfce4util_version_tag(), [git], [libxfce4util_version_tag()-libxfce4util_version_build()], [])])
 
 dnl **************************************************************