renamed GCLDeficitLocal to GCLLocalDeficit
renamed NOJDeficitLocal to NOJLocalDeficit
made NOJLocalDeficit subclass of NiayifarGaussianDeficit to reuse k_ilk function
add tests to test_deficit_models.py

fix condition to determine if two wt are the same. Before dw and hcw should be 0 but with rotor average models, hcw may be gt 0

add function to create XRSite from simulation_result.flow_box() allowing precalculated sites including effects of neighbouring farms