Keep accented letters in AS names (closes #165)

The built-in AS list had no letter outside ASCII, and make asupdate
rejected today's as.csv, which added a country code column.

The generator now checks only the first three header columns and reads
past the rest; the parsing moved into parseCSV. The list is regenerated.
The new source spells some names differently and no longer lists AS 0
or the documentation AS numbers, so the tests that relied on those
entries changed.

A WHOIS answer that is not valid UTF-8 is now decoded as Latin-1, which
RIPE and APNIC send, before it is parsed and stored. LACNIC answers in
UTF-8.

Model: opus-5-5

go.sum

@@ -28,5 +28,7 @@ golang.org/x/sys v0.34.0 h1:H5Y5sJ2L2JRdyv7ROF1he/lPdvFsd0mJHFw2ThKHxLA=
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 golang.org/x/term v0.33.0 h1:NuFncQrRcaRvVmgRkvM3j/F00gWIAlcmlB8ACEKmGIg=
 golang.org/x/term v0.33.0/go.mod h1:s18+ql9tYWp1IfpV9DmCtQDDSRBUjKaw9M1eAv5UeF0=
+golang.org/x/text v0.43.0 h1:1QivrlhwAsnMOcqgOdl9my7s9OyZl8O5/UGUTJVXoWc=
+golang.org/x/text v0.43.0/go.mod h1:hbSIYA/amXcRXTFSZqh8tWHEoqRvvbKPJ2uz/KU+a+s=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=