Unit test added for CombineSurfaceLineWithSoilProfile2D using complex 2D profile (with 6 surfaces in 2 layers) and a zigzag surface line.Unused methods in FactoryForSurfaceLines removed.Related to Issue [MWDAM-2257]
Case where phreatic line passes through all layers of 2D profile is better handled.Also added that the waternet line for PL1 can't be situated in the bottom aquifer.Related to Issue [MWDAM-2252]