[doc] update config examples in doc/*.lua to match current syntax
[tests] test auth.require_user from doc/core.lua
[lua] add lighty.error -> lighty.print alias
[tests] only use cache.disk.etag if request was handled
[lua] fix usage of lua_typename
[lua] push list values with __index metamethod to lookup string/nil keys in key-value lists
[mod_vhost] fix config mem leak
[log] fix small mem leak
[tests] add --valgrind-leak option