feat(elementexplorer): allow cmd params

allow to paste parametrs form command line, namely:
* chromeOnly - use chrome driver directly
* confiFile  - initialize browser by specified protractors' config file

... and other params same as in protracotr
This won't work if they're trying to use the local driver provider (e.g. using seleniumPort and seleniumServerJar), since the server will never be set up. We'll need to add driverprovider_.setupEnv(). At this point, I'm getting a bit worried that this is repeating a lot of code from protractor...