Impossible to create multiple screenshots for a method

[olegosipenko]

Sometimes it's necessary to take multiple screenshots in one test method - for example before and after some interaction. As far as I understand currently it's not possible because of two reasons:

• there is no way to submit a custom fil name for screenshot. It's always the same filename
• it throws AssertionError after storing first reference and test runner stops execution after it and therefore it doesn't execute the following code with next calls to snapshot

So, suggestion here is to provide a way to provide custom filenames and to not finish testing with throwing of AssertionError