Add initial set of comments

src/petsc/csrMatrix/solvers/petscSolver.C

src/petsc/csrMatrix/solvers/petscSolver.H

src/petsc/utils/PetscUtils.C

src/petsc/utils/PetscWrappedVector.H

src/petsc/utils/petscControls.C

src/petsc/utils/petscLinearSolverContext.H