changed answer logging for radio layout from the radio button text to the indices
changed for answer logging the question identification from question to key
adjust answer logging 
create new method in base class (QuestionLayoutBuilder) getLastKnowAnswer which is abstract and must be
implemented from all subclasses
the subclasses are so able to return the last given answer which can be used to extract them in the next button onClicklistener for the addAnswer logging. Which is much more comfortable because the answers are not logged twice or more if the user changes the answer. The answer is only saved after the next button click
adjust TextViewLayout add again onChangeListener which saves the answer and if the next button is triggered the answer is available without the submit button