PoldiAbstractDetector now returns vector of available elements
Put MockChopper and MockDetector in external file
Added decorator interface for PoldiAbstractDetector
MockDetector availableElements had wrong range
Added PoldiDeadWireDecorator

With PoldiDeadWireDecorator detectors are seamlessly freed from
malfunctioning elements.
Removed dead element handling code from PoldiAutoCorrelationCore

This is now done by PoldiDeadWireDecorator and appropriately no longer
of concern to the auto-correlation algorithm.