release: prepare for 3.1.92

NEWS

+3.1.92
+======
+
+Improve theming for radio/check menuitems for insensitive and mixed states
+Move applications overrides into a separate stylesheet
+Improve pathbar active button styling
+Remove highlight from active button border
+Add selectors for the DND style class
+Support RTL mode for GtkComboBox entries
+Improve attached modal dialogs
+
 3.1.91
 ======
 

configure.ac

 dnl Process this file with autoconf to produce a configure script.
 AC_PREREQ(2.53)
 
-AC_INIT([gnome-themes-standard], [3.1.91],
+AC_INIT([gnome-themes-standard], [3.1.92],
         [http://bugzilla.gnome.org/enter_bug.cgi?product=gnome-themes-standard])
 
 AM_INIT_AUTOMAKE([1.9 tar-ustar foreign dist-bzip2 no-dist-gzip])