Added "zlib" module.

Added "zlib" module.

    - zlib.deflateRawSync(string|buffer, options?) compresses data using
        deflate, and do not append a zlib header, returns Buffer.
    - zlib.deflateSync(string|buffer, options?) compresses data using
        deflate, returns Buffer.
    - zlib.inflateRawSync(string|buffer) decompresses a raw deflate
        stream, returns Buffer.
    - zlib.inflateSync(string|buffer) decompresses a deflate stream,
        return Buffer.