[iagno] Bump Gtk+ required version to 3.15.0...

[Arnaud Bonatti <arnaudb src gnome org>]

commit c3a455cb95db46050609ed6ad2b158c00fe12260
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Tue Feb 10 06:09:33 2015 +0100

    Bump Gtk+ required version to 3.15.0...
    
    ...and Valac's to 0.27.1.

 configure.ac |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 12146d9..377180e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -6,7 +6,7 @@ AM_SILENT_RULES([yes])
 AM_MAINTAINER_MODE
 GNOME_MAINTAINER_MODE_DEFINES
 
-AM_PROG_VALAC([0.25.1])
+AM_PROG_VALAC([0.27.1])
 AM_PROG_CC_C_O
 
 GLIB_GSETTINGS
@@ -18,7 +18,7 @@ dnl Dependencies
 dnl ###########################################################################
 
 GLIB_REQUIRED=2.40.0
-GTK_REQUIRED=3.13.4
+GTK_REQUIRED=3.15.0
 RSVG_REQUIRED=2.32.0
 CANBERRA_GTK_REQUIRED=0.26