Refactoring system for function types.

src/core/vectors/tnlSharedVector.h

src/core/vectors/tnlVector.h

src/functors/CMakeLists.txt

src/functors/tnlConstantFunction.h

src/functors/tnlExpBumpFunction.h

src/functors/tnlFunction.h

src/functors/tnlFunctorAdapter.h

src/functors/tnlSinBumpsFunction.h

src/functors/tnlSinWaveFunction.h

src/operators/diffusion/tnlExactLinearDiffusion.h

src/problems/tnlHeatEquationEocRhs.h