include gtk/gtk.h as a workaround for GTK+ >= 2.13.3.
display alert dialog when signing/encryption failed.
fixed the crash when try to use ascii-armored PGP encryption.
win32: made a workaround for the redraw problem in GTK+ 2.10.11.
fixed Turkish locale problem.
replaced intl.h with glib/gi18n.h.
ported to gpgme-1.0.
use GTK stock button for button set.
Initial import of Sylpheed (GTK2 version).