[patch 0/3] last large update to pgcrypto

Those 3 patches hopefully end my pgcrypto patch-bombing.
(Well, at least I am offline next couple weeks...)

1. Small fixes
2. Fortuna fixes
3. New README

There are 3 important points about new readme:

* It is formatted for use by asciidoc.  To be able to generate
  html from it.  As I consider the text version to be main
  target, I tried to as few formatting cruft as possible.

  Here are both versions online:

    http://grue.l-t.ee/~marko/src/pgcrypto/README.html
    http://grue.l-t.ee/~marko/src/pgcrypto/README.txt

* I've seen people suggest to use MD5 for passwords.
  Now there is special section which compares crypt algorithms
  to md5 and sha1.

* I announce the removal of (digest/cipher/hmac)_exists
  functions in 8.2.  Reason for it is that they are useless:

  - The informational question can be answered by calling the
    main function and looking for error.
  - They are useless for user programs, as you cannot replace
    one algorithm with another on the run - missing algorithm
    will be always hard error.
  - The question 'does it exists' even should not be asked,
    user should rather use algorithms that are _always_ there.

  The situation would be different for functions that would
  return a _list_ of supported algorithms.  But I doubt even
  the usefulness of such functions.

--
marko