Scala test fw

First attempt to use the inhouse Scala testing framework with one test for checking the picture overlay functionality. Keep in mind that I am a beginner Scala dev so code will likely look very "Javaish"
You don't need to use `var` or `null` in Scala pretty much ever, and shouldn't. `null` only exists to provide compatibility with Java, it's not something you should use in Scala.

If you want to have a val based on the browser property, you can just do something like this:

```scala

case class DriverAndCapabilities(driver: WebDriver, capabilities: DesiredCapabilities)

val driverAndCapabilities = getProperty(BROWSER) match {
  case "firefox" =>
    val capabilities = initDesiredCapabilities(testCaseName, DesiredCapabilities.firefox())
    DriverAndCapabilities(new FirefoxDriver(capabilities), capabilities)
  case ... => ... 
}
```