renamed variable 'interface' to 'iface'.
renamed 'interface' in struct to 'iface' to prevent compilation problem on some environments.
implemented auto-registration of new recipients.
added wrappers for C library function that take pathname arguments.
replaced intl.h with glib/gi18n.h.
added constant C_INTERNAL and CS_INTERNAL.
Initial import of Sylpheed (GTK2 version).