Adb shell input roll

Implementation for #737
This is probably not the final implementation. Making a pull request to open a discussion.

The implementation works for me using selendroid-standalone.

Here's the code how to use it:

- activate something scrollable/rollable (it might be a spinner)
- call `getSelendroidDriver().getTrackBall().roll(1, 5);`

this would roll the list and select the 5th item. First 'roll' attempt might not actually roll anything depending on number of items displayed.

I am not sure about the `selendroid-server` changes. They might not have been necessary and I haven't tested them.

Any thoughts?
so, you have an implementation to call the instrumentation, but you end up just doing an adb command? If the other didn't work, please remove from selendroid-server