Nodejs crypto methods

Imho crypto methods provided by nodejs should be used instead of the haxe(js) implementation.
I guess they are faster and probably less error prone.

For haxe.crypto.Md5 this would look like:

``` haxe
package haxe.crypto;

import js.node.Crypto;
import haxe.io.Bytes;

class Md5 {

public static function encode( s : String ) : String {
var h = Crypto.createHash( "md5" );
h.update( s );
return h.digest( "hex" );
}

public static function make( b : Bytes ) : Bytes {
var h = Crypto.createHash( "md5" );
h.update( b.getData() );
return Bytes.ofData( h.digest() );
}
}
```

What do you think?