- run validation blocks only when earlier validation steps were successful
- initialize untrusted_user_id in resources filter
- util::http::*: since spool file is server provided, use option
  "-spool" to indicate that spooling is intended. The actual name of
  the spool file is retuned in the "file" component of the dict.
- fix spool file logic for ns_http/ns_ssl
- allow spooling as well for curl
- drop "-depth" for the toplevel interface, since it is used for
  iteration on the (private) implementation level
- set max_depth per default to 10 to handle redirects automatically
- use util::http::* as well in apm_transfer_file
- improve page-contracts
Added version checking for curl and used it to verify if --post303 option is available.
- don't run validation, if required variables for the validation were not provided