added Cc: header to the header view.
modified the style of labels which are set not to have focus to make the selection visible.
fixed warnings about signedness difference.
added spacing for vbox of header view.
don't let some labels take focus.
fixed a compilation bug and key handling of summary.
replaced intl.h with glib/gi18n.h.
improved font management.
Initial import of Sylpheed (GTK2 version).