Cleaned up Python bindings to restore functionality: * StaticPersistence is iterable, its nodes are usable (sign, pair, cycle) * StaticPersistence knows how to map its nodes into Filtration indices * moved PythonCmp into utils.h * minor cosmetic changes

#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