Speed up email sorting
Speed up email sorting

Use Message#unique_name for sorting to avoid expensive File#basename
call.

Before:

[penberg@localhost alp]$ time ./bin/alp Cloudius

real	0m6.294s
user	0m5.706s
sys	0m0.312s

After:

[penberg@localhost alp]$ time ./bin/alp Cloudius

real	0m3.995s
user	0m3.444s
sys	0m0.307s

Signed-off-by: Pekka Enberg <add4fcd06328a394f0ad91feda7ee057316dc5ed@iki.fi>

penberg/alp