Merge branch 'feature/algebra-coverage' into 'develop'

src/algebra/CRSMatrix.hpp

src/algebra/LinearSolver.cpp

src/algebra/LinearSolver.hpp

src/algebra/SparseMatrixDescriptor.hpp

tests/CMakeLists.txt

tests/mpi_test_main.cpp

tests/test_CG.cpp

tests/test_CRSMatrix.cpp

tests/test_LinearSolver.cpp

tests/test_LinearSolverOptions.cpp

tests/test_main.cpp