Merge branch 'feature/session-storage' into feature/session-storage-cache

Conflicts:
	phpBB/phpbb/session.php
	tests/session/check_ban_test.php
	tests/session/check_isvalid_test.php
	tests/session/create_test.php
	tests/session/extract_hostname_test.php
	tests/session/extract_page_test.php
	tests/session/garbage_collection_test.php
	tests/session/session_key_test.php
	tests/session/testable_facade.php
	tests/session/unset_admin_test.php
	tests/session/validate_referrer_test.php