Fixed #111: Drop::sendAndForget can return a false value

Add new classes DropResultContact and DropResult 
Fixed #111: Drop::sendAndForget can return a false value

Close #195 
My personal choice is that existing version. But I do not want discuss about personal choice.
It is a little more code and on runtime it is faster.
But to handle the list is nearly the same way. With a list you have more possibilities to run through. But this are only integer.

An example


        List<Integer> list = new ArrayList<Integer>();
		int[] array = new int[0];
		int maxCounter = 20;

		for (int i = 0; i < maxCounter; i++) {
			list.add(i);
			array = addElement(array, i);
		}
			
		for (int i = 0; i < array.length; i++) {
		    System.out.print(array[i] + " ");
		}

		for (int i = 0; i < list.size(); i++) {
			System.out.print(list.get(i) + " ");
		}

If I have the choice use an array and it is faster or use a list and the code is nearly the same I prefer the faster version.