Support for stdout log

Hi,

Thank you for creating Tunneto.

I am trying to run tunnel-to inside an electron app, which will start the connection between our customer local machine and send tunnel-to link to our server, So we can download data from the local machine.
```
let spawn = require('child_process');
let path = "path_to_tunnel_to"
ls = spawn(path, ['--version']);
ls.stdout.on('data', (data) => {
console.log(data);
});
```
**Output:** _tunnelto 0.1.12_

Here in the above code it is returning the version because the process is terminated.

When I try to run
```
let spawn = require('child_process');
let path = "path_to_tunnel_to"
ls = spawn(path, ['--port', '3000']);
ls.stdout.on('data', (data) => {
console.log(data);
});
```
It will not return anything until the process is terminated. I also tried by adding verbose.

Kindly suggest any other way to do this.

In Ngrok there is option `log=stdout` it will return logs in stdout. So we can process it and get URL

Then I added subdomain to the arguments, Now I know in which subdomain tunnel-to is running. But I cannot get the tunnel-to Local Inspect Dashboard URL for debugging purposes.