Changes from 1.5.4. to 1.5.5
- Adam Stephens reported that hash #3 will be checked even though it has not
been computed. This should be fixed now, saves a DNS query.

Changes from 1.5.3. to 1.5.4
- Fixed some problems discovered by Bernd Holzinger and Larry Nedry,
especially with hashing routine #3 not returning a return value. Larry
noticed that as well as a discrepancy between the regular expression used by
iXhash.pm and the hashcheck.pl tool

Changes from 1.5.2 to 1.5.3
- Optimizations regarding the regular expression at hash #1 (entry
condition). Thanks go out to Bernd Holzinger (regex Part 1) and Jan Schmidt.
This should improve stability and performance quite a bit.

Changes from 1.5.1 to 1.5.2

- Fixed a bug where a regexp testing the IP returned was wrong.
It never matched - so now hits from iXhash. Gargl!

Changes from 1.5 to 1.5.1

- Changed entry condition for hash #1. The one in 1.5 was borked.
Also some lines were added to circumvent problems in Perl in some distros when
  using the originally intended regular expression (\s.+?){20}
- Also added a declaration for $digest.
 



Changes 1.1 to 1.5

- Removed unwanted/unnecessary 'use'-statements for some Perl modules
- Re-ordered the code, hopefully improving readability
- Implemented check to see if the returned IP fits the 127.0.0.0/8 subnet. This should 
prevent problems with OpenDSN and other DNS providers that somehow, 
sometimes, for some reason return other IPs
- Implemented the ability to store a hash with the repective mail's metadata (Option 
'use_ixhash_cache'). Other iXhash tests can then re-use the already 
computed hashes. 
- Implemented a way to have the plugin compute the  hashes via the local system's 'tr' and 'md5sum' commands. This is what 
the original, procmail-based NiX Spam code does and should be somewhat 
more compatible. If you decide to set 'xhash_pureperl' to '0', you can 
use 'ixhash_tr_path' and 'ixhash_md5sum_path' to specify which binaries 
to use. If you don't, SpamAssassin will use what it can find. - Revamped 
some regular expressions to a.) actually have them do what they should 
do and b.) circumvent problems with some Perl versions/releases. 
Hopeully some Perl warnings (uninitialised value...) are gone too. - 
Added output to the code handling timeout errors to state which DNS 
server was queried. 

