Implementing the explicit heat equation solver in CUDA.

examples/heat-equation/heatEquationSolver.h

examples/heat-equation/heatEquationSolver_impl.h

src/implementation/core/arrays/tnlArray_impl.h

src/implementation/core/arrays/tnlSharedArray_impl.h

src/implementation/functions/tnlTestFunction_impl.h

src/implementation/mesh/tnlTraversal_Grid1D_impl.h

src/implementation/mesh/tnlTraversal_Grid2D_impl.h

src/implementation/solvers/ode/tnlEulerSolver_impl.h

src/implementation/solvers/ode/tnlExplicitSolver_impl.h

src/implementation/solvers/ode/tnlMersonSolver_impl.h

src/implementation/solvers/tnlSolverConfig_impl.h

src/implementation/solvers/tnlSolverStarter_impl.h

src/solvers/ode/tnlExplicitSolver.h

src/solvers/ode/tnlMersonSolver.h