Added conversion operator from IQIndexVal to ITensor.
New design for Model classes based around strings for specifying different operators and states.
Updated SpinOne model to use new Model class design.
Added OptSet argument to Model::op method. Changed MPSt constructor taking InitState argument to get Model reference from initState instead of providing explicitly. Updated sandbox/sample codes and unit tests accordingly.
Added alternative names for SpinOne states and x eigenstates to SpinOne op method.
Created typedefs for BondGate template class.
More improvements to imagTEvol method and related supporting methods and classes. Greatly improved orthogonalization of derivative tensors to MPS tensors (so that norm of wf is preserved), including two alternative methods currently under investigation.