`npm run firefox` is not starting firefox with --start-debugger-server

[jasonLaster]

When we upgraded selenium + geckodriver, we stopped passing --start-debugger-server into the firefox command.

I created this issue with geckodriver to follow up earlier today and will look into it tomorrow mozilla/geckodriver#260. The solution should be a fairly simple api change.

[jasonLaster]

I spoke with @AutomatedTester yesterday and he confirmed this was an existing issue with selenium 3 and the fix landed a couple of days ago. We could build manually to confirm this and perhaps use that...

[jasonLaster]

@kareniel did a great job tackling this!