LICENSE: retain copyrights in license file

Signed-off-by: William Roberts <william.c.roberts@intel.com>

LICENSE

@@ -1,3 +1,15 @@
+Copyright 2017      Alibaba Group
+Copyright 2015-2017 Atom Software Studios, s.r.o.
+Copyright 2017      Emmanuel Deloget <logout@free.fr>
+Copyright 2018-2019 Fraunhofer SIT
+Copyright 2019      GlovePuppet
+Copyright 2015-2019 Intel Corporation
+Copyright 2019      Massachusetts Institute of Technology
+Copyright 2017-2018 National Instruments
+Copyright 2017      Red Hat, Inc.
+Copyright 2019      Sebastien LE STUM
+Copyright 2017      SUSE GmbH
+
 Redistribution and use in source and binary forms, with or without modification,
 are permitted provided that the following conditions are met: