Added test for understanding the collections hierarchy for sequences(ListBuffer).
Added test for understanding the collections hierarchy for sequences(Queue).
Added test for understanding the collections hierarchy for sequences(Stack).
Added test for understanding the collections hierarchy for sequences(Stream).
Added test for understanding the collections hierarchy for sequences(StringBuilder).
Added test for understanding the collections hierarchy for sequences(String).
Added test for understanding the collections hierarchy for sequences(ArrayBuffer).
Added test for understanding the collections hierarchy for sequences(List).
Added test for understanding the collections hierarchy for sequences(LinkedList).
Added test for understanding the collections hierarchy for sequences(MutableList).
Added test for understanding the collections hierarchy for sequences(IndexedSeq).
Added test for understanding the collections hierarchy for sequences(Buffer).
Added test for understanding the collections hierarchy for sequences(LinearSeq).
Added test for understanding the collections hierarchy for sequences(Seq).