Allow specification of timeout and number of threads in config file

[ghost]

Wraith uses a standard timeout of 1000 ms and 8 threads. This can cause issues when comparing a large number of pages in that contention is so great the whole page is not retrieved before timing out. This leads to differences being reported that aren't really there.

This PR allows the number or threads and the timeout to use to be specified in the config file, as follows:
num_threads: 3
timeout_ms: 3000

It these values are not specified in the config file, the old defaults of 8 and 1000 are used.

[ChrisBAshton]

Hi @stephen-richards - thanks for this. I'm reluctant to pass even more command line parameters to Phantom/Casper, it's already quite tricky to maintain. Besides, a similar timeout can be achieved using the before_capture hook, e.g.

before_capture: javascript/wait_a_few_seconds.js

// wait_a_few_seconds.js
module.exports = function (phantom, ready) {
    // make Wraith wait a bit longer before taking the screenshot
    setTimeout(ready, 3000); // you MUST call the ready() callback for Wraith to continue
}

(Please note, this example is as of Wraith 3.1, which will happen when #361 is merged).

However, I do like the idea of being able to configure the number of threads Wraith uses! Please consider editing your PR.

[ChrisBAshton]

Also, for clarity I'd refer to these as 'overridden' values rather than 'non-standard' (which suggests Strings instead of ints, or non-ASCII characters or something)

[yareckon]

Please Please Please! My VM is too puny for 8 phantomjs threads, and I would love to be able to set this much lower.