src/setup.c: check whether the specified location includes settings folder.
setup.c: changed the icon. Use name 'Mailbox' only when basename is 'Mail'.
modified path display of setup dialog.
append '/Mail' at the tail of selected folder on setup dialog.
new setup dialog which improves usability.
modified the text of mailbox setup dialog.
improved performance of the update of statusbar.
replaced intl.h with glib/gi18n.h.
restored the resize grip of the main statusbar.
Initial import of Sylpheed (GTK2 version).