Add LICENSE, matching 3-Clause BSD

Signed-off-by: Jorge Perez <[email protected]>

Author: Blast545

CONTRIBUTING.md

@@ -0,0 +1,7 @@
+Any contribution that you make to this repository will
+be under the [BSD-3-Clause](./LICENSE).
+
+Contributors must sign-off each commit by adding a `Signed-off-by: ...`
+line to commit messages to certify that they have the right to submit
+the code they are contributing to the project according to the
+[Developer Certificate of Origin (DCO)](https://developercertificate.org/).