Input Refactoring

- Removed low-level Threadding functionality from the HTTP and UDP
readers and moved to ExecuterService instead
- Introduced a new interface InputBuildable to define the behavior of
an Input builder
- Introduced a new abstract class InputBuilder that contains common
functionality for building Input instances using NetworkReadable
instances
- Introduced two new classes, DirectBuilder and DelimiterBuilder, that
build Inputs either directly from the raw port data or using a
specified delimiter