Support "require"-like syntax for authorization

[mikelococo]

Currently, all authorization must be performed by an external AuthOpenIDUserProgram. While supporting an external authorization program is useful for complex scenarios that involve integration with an external account-database, it is overkill for the common/simple scenario of a small whitelist of valid-users. For this use-case, the "require" syntax used by the http-basic authtype sensible and familiar.

Please consider adding support for a simplified authorization syntax modelled after the "require" directive.

[bmuller]

The upcoming 0.6 release (and current unstable in git) do support the "require" syntax.