Removed unused mapprimeind methods from tensor classes and an unnecessary include from observer.h
Changed free primelevel methods in index.h to templates. Removed duplicate methods from itensor.h. Added a unit test for ITensor::norm.
Changed struct inqn into a subclass of Index, class IndexQN. Renamed IQIndex::iq() to IQIndex::indices(). Will allow templated methods such as hasindex to work for IQIndex too. Also makes it easy to treat and IndexQN as an Index by using a reference and avoids code duplication/fragmentation.
Fixed a bug in MPS addition caused during last commit (switching to IndexQN).
Updated printing of class QN.