modified the accelerators, and the layout of address book.
always enable To, Cc, and Bcc button of the address book.
preserve the window position of address book.
the size of address book is now remembered.
fixed the folder tree bug of addressbook.
fixed refresh of addressbook folder contents.
fixed a bug of addressbook that multiple selection with Ctrl key didn't work with GTK+ 2.6.9.
modified several alerts, and added accelerators for the buttons.
added G_ALERTCANCEL to AlertValue, and return it if cancelled.
fixed Turkish locale problem.
reimplemented summary view with GtkTreeView.
replaced intl.h with glib/gi18n.h.
use GTK stock button for button set.
Initial import of Sylpheed (GTK2 version).