Initial s390-tools-2.0.0 import

This commit is based on the s390-tools-1.39.0 version.

Changes on top of s390-tools-1.39.0:

 - Add MIT license to all source files
 - Add LICENSE file
 - Transform REAMDE to README.md (markdown)
 - Add AUTHORS.md file
 - Add CONTRIBUTING.md file
 - Move changelog from README to CHANGELOG.md file

Reviewed-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>

dump2tar/src/global.c

@@ -0,0 +1,20 @@
+/*
+ * dump2tar - tool to dump files and command output into a tar archive
+ *
+ * Global variables
+ *
+ * Copyright IBM Corp. 2016, 2017
+ *
+ * s390-tools is free software; you can redistribute it and/or modify
+ * it under the terms of the MIT license. See LICENSE for details.
+ *
+ */
+
+#include "global.h"
+
+/* Global settings */
+bool global_threaded;
+bool global_debug;
+bool global_verbose;
+bool global_quiet;
+bool global_timestamps;