v2.1.0-rc.2

Pre-release for testing against a full pre-production SimpleSAMLphp
environment.

Added

• Failed login attempts against a username/password source can now be
  reported to an external webservice, via the new accessLog authsource
  option (url, apiKey, sistemaAutenticacion, idpExterno,
  verifySsl, connectTimeout, timeout). Disabled unless a url is
  configured; a failure talking to the webservice is only logged and never
  affects the login flow. See the new \SimpleSAML\Module\multiauthsinglepage\AccessLogger
  and the README.
• ext-curl added to composer.json (used by AccessLogger).