SDK assumes networkID as tc if not specified.

[cubistplay]

Assuming tc as default networkID is not problem.

But in the first example code of codechain sdk document,
networkID is not specified while constructing SDK object.

This might cause confusion because sdk also assumes networkID as tc in the case below.

var sdk = new SDK({ server: "https://corgi-rpc.codechain.io" });

To set networkId to wc, we should specify it

var sdk = new SDK({ server: "https://corgi-rpc.codechain.io"
 networkId: "wc"});

So I think we should change document or change assuming logic.