remove currently unused LinAlg files and related tests

CMakeLists.txt

MathLib/CMakeLists.txt

MathLib/LinAlg/Preconditioner/generateDiagPrecond.cpp

MathLib/LinAlg/Preconditioner/generateDiagPrecond.h

MathLib/LinAlg/Solvers/BiCGStab.cpp

MathLib/LinAlg/Solvers/BiCGStab.h

MathLib/LinAlg/Solvers/CG.cpp

MathLib/LinAlg/Solvers/CG.h

MathLib/LinAlg/Solvers/CGParallel.cpp

MathLib/LinAlg/Solvers/GMRes.cpp

MathLib/LinAlg/Solvers/GMRes.h

MathLib/LinAlg/Solvers/IterativeLinearSolver.h

MathLib/LinAlg/Solvers/blas.h

MathLib/LinAlg/Solvers/solver.h

MathLib/LinAlg/Sparse/CRSMatrix.h

MathLib/LinAlg/Sparse/CRSMatrixDiagPrecond.h

MathLib/LinAlg/Sparse/CRSMatrixOpenMP.h

MathLib/LinAlg/Sparse/CRSMatrixPThreads.h

MathLib/LinAlg/Sparse/CRSSymMatrix.h

MathLib/LinAlg/Sparse/CRSTools-impl.h