Adding P2 versions of k_mass

operators.toml

operators/k_mass/CMakeLists.txt

operators/k_mass/P2ElementwiseKMass.cpp

operators/k_mass/P2ElementwiseKMass.hpp

operators/k_mass/P2ElementwiseKMassAnnulusMap.cpp

operators/k_mass/P2ElementwiseKMassAnnulusMap.hpp

operators/k_mass/P2ElementwiseKMassIcosahedralShellMap.cpp

operators/k_mass/P2ElementwiseKMassIcosahedralShellMap.hpp

..._mass/avx/P2ElementwiseKMassAnnulusMap_apply_macro_2D.cpp

...ulusMap_computeInverseDiagonalOperatorValues_macro_2D.cpp

.../P2ElementwiseKMassIcosahedralShellMap_apply_macro_3D.cpp

...hellMap_computeInverseDiagonalOperatorValues_macro_3D.cpp

operators/k_mass/avx/P2ElementwiseKMass_apply_macro_2D.cpp

operators/k_mass/avx/P2ElementwiseKMass_apply_macro_3D.cpp

...seKMass_computeInverseDiagonalOperatorValues_macro_2D.cpp

...seKMass_computeInverseDiagonalOperatorValues_macro_3D.cpp

...ss/noarch/P2ElementwiseKMassAnnulusMap_apply_macro_2D.cpp

...ulusMap_computeInverseDiagonalOperatorValues_macro_2D.cpp

...noarch/P2ElementwiseKMassAnnulusMap_toMatrix_macro_2D.cpp

.../P2ElementwiseKMassIcosahedralShellMap_apply_macro_3D.cpp