A functional replacement for parts of the Java Collections library.

All implementations must be immutable and provide fluent interfaces to create modified versions.

Currently the interfaces supported are:

- Gathering (equivalent to Collection)
- Series (equivalent to List)

Two implementations exist:

- ArraySeries (equivalent to ArrayList)
- HeadTailSeries (equivalent to the lists found in functional Languages)

Sample code:

    final Series<Integer> original = ArraySeries.of(3, 4, 5);
    final Series<Integer> clone =
        original
            .prependArray(1, 2)
            .appendArray(9, 10)
            .insertCollection(5, Arrays.asList(6, 7, 8))
            .removeGathering(ArraySeries.of(6, 7, 8))
            .removeArray(9, 10)
            .deleteItems(0, 1);
    assertEquals(original, clone);