added license

LICENSE

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+## Copyright, Patent & License Notice
+The MARS VINS software is copyrighted by the Regents of the University of
+Minnesota. Use of the software may be covered by at least US patents and
+applications 9,243,916, 9,658,07, 14/733,468 and 15/601,261 assigned to Regents
+of the University of Minnesota. The software can be freely used for educational
+and research purposes by non-profit institutions and US government agencies
+only. Other organizations are allowed to use the MARS VINS software only for
+evaluation purposes, and any further uses will require prior approval from
+http://z.umn.edu/marsvins. The software may not be sold or redistributed
+without prior approval. One may make copies of the software for their use
+provided that the copies, are not sold or distributed, are used under the same
+terms and conditions.
+
+As unestablished research software, this code is provided on an "as is" basis
+without warranty of any kind, either expressed or implied. The downloading, or
+executing any part of this software constitutes an implicit agreement to these
+terms. These terms and conditions are subject to change at any time without
+prior notice.