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

pkg/asinfo/example_test.go

@@ -17,7 +17,7 @@ func ExampleGet() {
 func ExampleGetDescription() {
 	desc := asinfo.GetDescription(13335)
 	fmt.Println(desc)
-	// Output: Cloudflare, Inc.
+	// Output: Cloudflare Inc.
 }
 
 func ExampleSearch() {