feat(config): Add configuration for adding javascript version.

[Moumi]

Add the configuration to add a javascript version tag to the loaded scripts. Only applied when the Firefox browser is run.

Closes #1719.

[Moumi]

While looking at the Travis CI results, it probably is the fact that Chrome is not available on that server. Should I change this to PhantomJS or is it no issue?

/cc @dignifiedquire

[dignifiedquire]

This should be tagged with @not-jenkins so it's not run on travis

[Moumi]

I have successfully made the change that was suggested. It seems that it made the difference and the changes I made actually work now. However, I got the following error (on Jenkins) for the first time ever:

launchers/process.js flow start -> timeout -> 3xrestart -> failure:
     Uncaught AssertionError: expected spy to have been called with arguments /usr/bin/browser, ["http://localhost/?id=fake-id"]
    at test/unit/launchers/process.spec.js:232:42
    at [object Object]._onTimeout (node_modules/lodash/index.js:1773:43)

Not sure why it gives an error there, but it has nothing to do with my change. If it is a common, or even new issue, I will create an issue for it 😉

[dignifiedquire]

Yeah you can ignore that one, no idea why it fails sometimes (was never able to reproduce it locally :( )

[Moumi]

Ah oke, good. Hope to have helped with this PR ;)

[dignifiedquire]

Thanks, looks good but needs some documentation in the config section of the docs.

[Moumi]

I will write some documentation for it tomorrow. Expect it to have it tomorrow evening.

[dignifiedquire]

Thanks @Moumi

[Moumi]

Finished it @dignifiedquire ;)

[dignifiedquire]

Better: "included JavaScript files"

[Moumi]

Applied your comments 😉

[dignifiedquire]

Thanks