Changed behavior to correctly process new formats from ARIN:

1. Change of name:
ftp://ftp.arin.net/pub/stats/arin/delegated-arin-extended-latest
instead of
ftp://ftp.arin.net/pub/stats/arin/delegated-arin-latest

2. Change of MD5 checksum file format:
ftp://ftp.arin.net/pub/stats/arin/delegated-arin-extended-latest.md5
contains:
11acb87299e13be8911a9ce45d49612e  delegated-arin-extended-20130827
instead of
ftp://ftp.arin.net/pub/stats/arin/delegated-arin-latest.md5
which contained:
MD5 (delegated-arin-latest) = 9e056d06a46740cb8cfed99702149c44

changed the code to look for 32 hex string if it previous parsing fails.

3. Change of file format from 2 to 2.3
ftp://ftp.arin.net/pub/stats/arin/delegated-arin-extended-latest
contains:
2.3|arin|1377579757580|105164|19700101|20130827|-0400
instead of:
2|arin|20130812|72395|00000000|20130811|-0400

so isdigit() failed on "2.3" string.

Now works.