Patch redirect

[ahmyi]

This pull request allows pool to navigate miners.

You can test by mining to testnet.scalaproject.io:3333

There are 2 test conditions you can apply:

1. Upon login - Use a normal scala address to redirect to official pool upon start of mining operation before a job is received.
2. Upon mining - Use a scala subaddress to redirect during mining operation.

Below is an example of redirect in operation

For miner to recognize when to redirect. Send a redirect parameter with host and port. Eg.

{
   "redirect" : {
        "host" : "mine.scalaproject.io",
        "port" : 5555
   }
}