Updates for release

NEWS

+4.15.6
+======
+- Introduce xfce_spawn and xfce_spawn_command_line
+  in favor and instead of xfce_spawn_no_child
+- Bump GLib (and gio, gthread, etc) minimum to 2.50.0
+- about: Support multiple GPUs and print GPU memory size
+- about: Drop window subtitle
+- Always perform sanity check
+- Avoid checking for epoxy if libgtop is disabled
+- XfceTitledDialog: Fix erroneous check (Fixes #30)
+- No startup notification in Wayland to prevent crash (Issue #17)
+- Translation Updates:
+  Chinese (China), Chinese (Taiwan), Estonian, French, German, Hebrew,
+  Indonesian, Italian, Japanese, Lithuanian, Norwegian Bokmål,
+  Portuguese, Portuguese (Brazil), Russian, Serbian, Spanish, Swedish,
+  Turkish
+
 4.15.5
 ======
 - Add new API xfce_spawn_no_child (!8):

configure.ac.in

@@ -9,10 +9,10 @@ m4_define([libxfce4ui_verinfo], [0:0:0])
 m4_define([libxfce4ui_version_api], [2])
 m4_define([libxfce4ui_version_major], [4])
 m4_define([libxfce4ui_version_minor], [15])
-m4_define([libxfce4ui_version_micro], [5])
+m4_define([libxfce4ui_version_micro], [6])
 m4_define([libxfce4ui_version_nano], []) dnl leave this empty to have no nano version
 m4_define([libxfce4ui_version_build], [@REVISION@])
-m4_define([libxfce4ui_version_tag], [git])
+m4_define([libxfce4ui_version_tag], [])
 m4_define([libxfce4ui_version], [libxfce4ui_version_major().libxfce4ui_version_minor().libxfce4ui_version_micro()ifelse(libxfce4ui_version_nano(), [], [], [.libxfce4ui_version_nano()])ifelse(libxfce4ui_version_tag(), [git], [libxfce4ui_version_tag()-libxfce4ui_version_build()], [libxfce4ui_version_tag()])])
 
 m4_define([libxfce4kbd_private_verinfo], [0:0:0])