#3 mod_auth_cache implementation

[issac]

I needed mod_auth_cache, so I implemented it :)

In addition to the existing behavior, I added an optional timeout value for the cached credentials

As mentioned on the dev@httpd list, this should really be re-written against socache, but I needed 2.2 compatibility without trunk features

I included the fully working sourcefile.

[issac]

sourcecode file