Refactoring the parabolic hamilton-jacobi solver.

examples/hamilton-jacobi/HamiltonJacobiProblem.h

examples/hamilton-jacobi/HamiltonJacobiProblem_impl.h

examples/hamilton-jacobi/tnl-run-eikonal-equation-eoc-test

src/functions/CMakeLists.txt

src/functions/tnlSDFSinBumpsFunction.h

src/functions/tnlSDFSinBumpsFunction_impl.h

src/functions/tnlSDFSinWaveFunction.h

src/functions/tnlSDFSinWaveFunctionSDF_impl.h

src/functions/tnlSDFSinWaveFunction_impl.h

src/functions/tnlSinWaveFunctionSDF.h

src/functions/tnlSinWaveFunctionSDF_impl.h

src/functions/tnlSinWaveFunction_impl.h

src/functions/tnlTestFunction_impl.h