- add code to convert timeout value to a value suitable for the
  underlying implementation (NaviServer or curl)
- document timeout values
- base deprecated code on util::http::*
- use util::http::* instead of deprecated procs
- use util::http::get instead of util_httpget
- check ids in page contracts
- use util::http::get instead of deprecated proc
- check ids in page contracts
- activate spooling to files for versions of naviserver supporting it
- check ids in page contracts
- improve page-contracs
- improve page-contract
- check ids in page contracts
- improve page contracts
- make a more sane version of ad_page_contract_filter boolean
- add function util::http::available to check, whether util::http::* can be called in the current configuration