Add UseDisposeDriver(bool) method to AtataContextBuilder

[YevgeniyShunevych]

Add method to AtataContextBuilder:

public AtataContextBuilder UseDisposeDriver(bool disposeDriver)

UseDisposeDriver - sets a value indicating whether to dispose the AtataContext.Driver when AtataContext.Dispose method is invoked. The default value is true.

The configuration method is useful in case when you need to reuse the same driver in different tests. For example, you can create one driver at test suite level (even using AtataContext for test suite) and pass it to all the suite tests, then dispose the driver on test suite tear down.