AlphaScan API: rm old c'tor; wavelength must be set separately

Examples/specular/AlternatingLayers1.py

Examples/specular/AlternatingLayers2.py

Examples/specular/BasicPolarizedReflectometry.py

Examples/specular/BeamAngularDivergence.py

Examples/specular/FootprintCorrection.py

Examples/specular/PolarizedNoAnalyzer.py

Examples/specular/PolarizedSpinFlip.py

Examples/specular/RoughnessModel.py

Examples/specular/SpecularSimulationWithRoughness.py

Sim/Scan/AlphaScan.cpp

Sim/Scan/AlphaScan.h

Tests/SimFactory/MakeSimulations.cpp

Tests/Unit/Sim/SpecularScanTest.cpp

Tests/Unit/Sim/SpecularSimulationTest.cpp

Wrap/Python/std_simulations.py

auto/Wrap/libBornAgainSim.py

auto/Wrap/libBornAgainSim_wrap.cpp