[gnote] Bump GTK++ requirement to 3.16, Gtkmm to 3.18

[Aurimas Černius <aurimasc src gnome org>]

commit 6f3c5fe52f450ac4b08903b4594a25f79a6fac2a
Author: Aurimas Černius <aurisc4 gmail com>
Date:   Sun Jan 10 15:08:01 2016 +0200

    Bump GTK++ requirement to 3.16, Gtkmm to 3.18

 configure.ac |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 1c9a624..fbc2565 100644
--- a/configure.ac
+++ b/configure.ac
@@ -25,9 +25,9 @@ AC_DEFINE_UNQUOTED([LIBGNOTE_VERSION_INFO], ["$LIBGNOTE_VERSION_INFO"], [libgnot
 dnl all the library version.
 dnl if one is harcoded elsewhere, it is a bug
 
-GTK_VERSION=3.10
+GTK_VERSION=3.16
 LIBGLIBMM_VERSION=2.32
-LIBGTKMM_VERSION=3.10
+LIBGTKMM_VERSION=3.18
 GTKSPELL_VERSION=3.0.0
 BOOST_VERSION=1.34
 LIBSECRET_VERSION=0.8