node.js crypto: Changed HMAC and Hash params to `any`

1. `createHmac` also accepts Buffers as the `key` param, not only strings
2. `Hmac.digest` and `Hash.digest` both return a Buffer object, if no encoding is specified, so also not just strings.

Docs:
http://nodejs.org/api/crypto.html

can we use specialized parameter? 
like this. https://github.com/borisyankov/DefinitelyTyped/blob/master/_infrastructure/tests/typescript/1.0.1/lib.d.ts#L4723
(pr http://www.typescriptlang.org/Content/TypeScript%20Language%20Specification.pdf 3.7.2.4 Specialized Signatures)