Adding general list interface and concrete implementation of it.

Signed-off-by: Tomasz Kamiński <kaminski.tomasz.a@gmail.com>
Adding Iterator pattern example & implementation.

Signed-off-by: Tomasz Kamiński <kaminski.tomasz.a@gmail.com>
Adding Chain of Responsibility pattern example.

Signed-off-by: Tomasz Kamiński <kaminski.tomasz.a@gmail.com>
Adding Handler pattern implementation.

Signed-off-by: Tomasz Kamiński <kaminski.tomasz.a@gmail.com>