v0.8.0

• Add support for receiving HTTP-Artifact identifiers as POST data.
• Simplify caching headers.
• Map login errors into more appropriate HTTP error codes than
  400 Bad Request.
• Add MellonNoSuccessErrorPage option to redirect to a error page on login
  failure.
• Turn session storage into a dynamic pool of memory, which means that
  attribute values (and other items) can have arbitrary sizes as long as
  they fit in the session as a whole.
• Various bugfixes:
  • Fix for compatibility with recent versions of CURL.
  • Fix broken option MellonDoNotVerifyLogoutSignature.
  • Fix deadlock that could occur during logout processing.
  • Fix some compile warnings.
  • Fix some NULL derefernce bugs that may lead to segmentation faults.
  • Fix a minor memory leak during IdP metadata loading.