Features to be added

[MostafaKhezri]

Below is a list of features to be added to the code:

1. Extraction of the non-nearest terms. The calculate_ising_sw method does this for arbitrary Pauli terms, but of course only works for small systems where the full circuit H can be calculated.
2. Calculate residual XX or XY terms. Again the calculate_ising_sw can calculate this for arbitrary Pauli terms, and just has to be added to a wrapper method for easier use. This one can be calculated for pair-wise method easily.
3. Warning about breaking the qubit approximation (non-MRT) when qubit z-bias is tilted too much
4. Calculation of geometric terms via adiabatic intertwiner or other methods.