[gtkmm] NEWS: Mention API additions in 3.16.

[Murray Cumming <murrayc src gnome org>]

commit cc6e89926b9fcf2278eef20084754e5d9f86e2ac
Author: Murray Cumming <murrayc murrayc com>
Date:   Wed Mar 25 11:15:31 2015 +0100

    NEWS: Mention API additions in 3.16.

 NEWS |   50 +++++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 49 insertions(+), 1 deletions(-)
---
diff --git a/NEWS b/NEWS
index 0e85fac..814f278 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,51 @@
+3.16:
+
+API additions since 3.14:
+
+Gdk:
+* Device: Add get_vendor_id() and get_product_id().
+  (Murray Cumming)
+
+Gtk:
+* CssProvider: Add CssProviderError and signal_parsing_error()
+  (Kjell Ahlstedt)
+* Add CssSection.
+  (Kjell Ahlstedt)
+* Dialog: Add constructors with DialogFlags,
+  for instance to create a dialog with a header bar.
+  (Kjell Ahlstedt) Bug #738513.
+* Grid: Add attach_next_to() without the 'sibling' parameter.
+  (Kjell Ahlstedt)  Bug #739340.
+* Label: Add get/set_xalign/yalign() and properties.
+  (Murray Cumming)
+* ScaleButton: Add a constructor without the icons.
+  (Murray Cumming)
+* ScrolledWindow: Add get/set_overlay_scrolling() and property.
+  (Juan R. García Blanco)
+* SearchEntry: Add the search_changed signal
+  (Kjell Ahlstedt)
+* Stack: Add hhomogeneous and vhomogeneous properties.
+  (Juan R. García Blanco)
+* Add StackSidebar.
+  (Kjell Ahlstedt)
+* StackSwitcher: Add unset_stack().
+  (Kjell Ahlstedt)
+* Added StyleProperty
+  (Mark Vender) Bug #673317.
+* TextTag: Add fallback, fallback-set, letter-spacing, and
+  letter-spacing-set properties.
+  (Juan R. García Blanco)
+* TextBuffer:
+  - Add insert_markup().
+  - Add the copy_target_list and paste_target_list properties.
+  - Wrap the serialize()/deserialize() methods.
+  (Kjell Ahlstedt)
+* TextView: Add monospace property.
+  (Juan R. García Blanco)
+* Widget: Added get_action_group() and list_action_prefixes().
+  (Murray Cumming)
+
+
 3.16.0 (stable):
 
 Gtk
@@ -71,7 +119,7 @@ Gtk:
   function does more.
   (Kjell Ahlstedt) Bug #742637.
 * TextBuffer:
-  - Add insert_martkup().
+  - Add insert_markup().
   - Add the copy_target_list and paste_target_list properties.
   (Kjell Ahlstedt)