Cleaned a bit the HTTP_AUTHORIZATION class, to separate basic from digest specific features. (still some work to do).
Improved the way the code get the header values.
Review how auth (basic or digest) should be used
  i.e one login that trigger the challenge, and otherwise just
  checking if auth is provided or not.

Note: the solution is not fully working due to bad management of nonce values.
  So concurrent connection will not work.
  Suggestion: create a specific HTTP_AUTHORIZATION_NONCE_MANAGER (or other name), to replace the list of nonce, and put there code to create a new nonce, and also to find if a nonce is valid, or stale. ...
Cleaning
- moved .txt into doc folder
- updated http_authorization.ecf to follow -safe.ecf (and cleaned -safe.ecf)
Fixed issue with .ecf (which were mixing void-sade code and non void-safe)
Added comments
Merged back the digest utilities into HTTP_AUTHORIZATION since this class in the only user for its implementation.
Minor modifications. Added nonce manager class.
Added text file which shows overall information flow.
Minor changements. Next step: introduce nonce manager, and detect replays throught nonce-counts.