Implemented ImageZigzagPersistence * Changed ZigzagPersistence to support a visitor, and implemented ImageZigzagPersistence * examples/rips/rips-zigzag now computes using ImageZigzagPersistence * PersistenceDiagram no longer records zero persistence pairs * Added utilities/memory.h with report_memory() function

#ifndef __NUMBER_TRAITS_H__
#define __NUMBER_TRAITS_H__

template<class NumberType_>
class number_traits
{
	public:
		typedef							NumberType_									NumberType;

		static NumberType&				normalize(NumberType& n)					{ return n; }
};

#endif