symbols: replace the remaining dead symbols in most "nodeadkeys" variants

This leaves one dead symbol in the Finnish "nodeadkeys" variant, and five dead symbols in the Hungarian one, but... they are all on the fourth level, so... let them be.

The upper-level dead symbols are replaced with the marginally useful ezh (ʒ), dagger (†), radical (√), and ellipsis (…).

This partially addresses and closes issue #339 (closed).

Signed-off-by: Benno Schulenberg bensberg@telfort.nl