po/POTFILES.in: translate plugin/attachment_tool/attachment_tool.c.
merged plugin-test branch into trunk.
remote mailbox: enabled cancellation on connection.
implemented vertical view. Separated quick search into another module.
added description to the field page of CSV import.
implemented the toolbar customization dialog.
implemented SSL certificate dialog.
implemented printing of MIME part. Code cleanups.
updated po files.
perform show/hide on trayicon click. Implemented popup menu on trayicon.
added missing files in POTFILES.in.
moved recv.[ch] to libsylph.
updated po directory.
Initial import of Sylpheed (GTK2 version).