Fix two links to repos in CONTRIBUTING.md.

CONTRIBUTING.md

@@ -4,11 +4,11 @@ If you have questions or comments, please feel free to email the
 authors. 
 
 For feature requests, suggestions, and bug reports, please open an issue on
-[our Github](https://github.com/isislovecruft/x25519-dalek).  (Or, send us
+[our Github](https://github.com/dalek-cryptography/x25519-dalek).  (Or, send us
 an email if you're opposed to using Github for whatever reason.)
 
 Patches are welcomed as pull requests on
-[our Github](https://github.com/isislovecruft/x25519-dalek), as well as by
+[our Github](https://github.com/dalek-cryptography/x25519-dalek), as well as by
 email (preferably sent to all of the authors listed in `Cargo.toml`).
 
 All issues on curve25519-dalek are mentored, if you want help with a bug just