Make licensing more explicit

Cargo.toml

@@ -5,7 +5,7 @@ documentation = "https://docs.rs/num"
 homepage = "https://github.com/rust-num/num"
 keywords = ["mathematics", "numerics", "bignum"]
 categories = [ "algorithms", "data-structures", "science", "no-std" ]
-license = "MIT/Apache-2.0"
+license = "MIT OR Apache-2.0"
 repository = "https://github.com/rust-num/num"
 name = "num"
 version = "0.3.0"

README.md

@@ -74,6 +74,21 @@ The `num` crate as a whole is tested for rustc 1.31 and greater.
 The `num-traits`, `num-integer`, and `num-iter` crates are individually tested
 for rustc 1.8 and greater, if you require such older compatibility.
 
+## License
+
+Licensed under either of
+
+ * [Apache License, Version 2.0](http://www.apache.org/licenses/LICENSE-2.0)
+ * [MIT license](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.
+
 
 [`num-bigint`]: https://github.com/rust-num/num-bigint
 [bigint-c]: https://crates.io/crates/num-bigint