Add 'no-store' to the cache-control header

replaces unconditional claim for SAML1 and 2 support

Based on work proposed by Stefan Winter.

Closes: #310

oAuth: make module proxy-aware

Google will create an entityId with your domain, as described in #9.

NameIDAttribute filter: update to use SAML2\XML\saml\NameID

Added 'no-store' to the cache-control header to prevent Google Chrome from serving the 302 redirect from disk cache

\SimpleSAML\Utils\HTTP::fetch properly handles proxy settings before calling file_get_contents()

also add some tests ;)

Fix bug in createLoggingHandler

oauth: Cleanup unused demo + templates

Lowercased some keywords too!

Fixes edge-case https://github.com/simplesamlphp/simplesamlphp/issues/741 where application has one of the known LoggingHandlers' name as a defined class