MINOR: session: start to reintroduce struct session

There is now a pointer to the session in the stream, which is NULL
for now. The session pool is created as well. Some parts will move
from the stream to the session now.
diff --git a/include/proto/session.h b/include/proto/session.h
new file mode 100644
index 0000000..79589d3
--- /dev/null
+++ b/include/proto/session.h
@@ -0,0 +1,43 @@
+/*
+ * include/proto/session.h
+ * This file defines everything related to sessions.
+ *
+ * Copyright (C) 2000-2015 Willy Tarreau - w@1wt.eu
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, version 2.1
+ * exclusively.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#ifndef _PROTO_SESSION_H
+#define _PROTO_SESSION_H
+
+#include <common/config.h>
+#include <common/buffer.h>
+#include <common/debug.h>
+#include <common/memory.h>
+
+#include <types/global.h>
+#include <types/session.h>
+
+extern struct pool_head *pool2_session;
+int init_session();
+
+#endif /* _PROTO_SESSION_H */
+
+/*
+ * Local variables:
+ *  c-indent-level: 8
+ *  c-basic-offset: 8
+ * End:
+ */