Move boilerplate to README.md

Author: emberian

README.md

@@ -8,3 +8,23 @@ Rust Signal
 A higher-level library for handling unix signals. Currently more focused on
 writing process supervisors, but may be used (and extended) for other purposes
 too.
+
+=======
+License
+=======
+
+Licensed under either of
+
+ * Apache License, Version 2.0, (./LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
+ * MIT license (./LICENSE-MIT or http://opensource.org/licenses/MIT)
+
+at your option.
+
+------------
+Contribution
+------------
+
+Unless you explicitly state otherwise, any contribution intentionally
+submitted for inclusion in the work by you, as defined in the Apache-2.0
+license, shall be dual licensed as above, without any additional terms or
+conditions.