[epiphany] Bump GTK+ requirement to 3.16

[Michael Catanzaro <mcatanzaro src gnome org>]

commit dd6f04171197e404a58c6f778f79d8a6040b15c6
Author: Michael Catanzaro <mcatanzaro igalia com>
Date:   Mon Oct 26 19:00:30 2015 -0500

    Bump GTK+ requirement to 3.16
    
    For gtk_label_set_xalign

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index c73b56f..ede158f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -74,7 +74,7 @@ AX_REQUIRE_DEFINED([YELP_HELP_INIT])
 YELP_HELP_INIT
 
 GLIB_REQUIRED=2.38.0
-GTK_REQUIRED=3.13.0
+GTK_REQUIRED=3.16.0
 LIBXML_REQUIRED=2.6.12
 LIBXSLT_REQUIRED=1.1.7
 WEBKIT_GTK_REQUIRED=2.9.5