TRaversers benchmark refactoring,

src/Benchmarks/Traversers/AddOneEntitiesProcessor.h

src/Benchmarks/Traversers/BenchmarkTraverserUserData.h

src/Benchmarks/Traversers/GridTraverserBenchmarkHelper.h

src/Benchmarks/Traversers/GridTraversersBenchmark.h

src/Benchmarks/Traversers/GridTraversersBenchmark_1D.h

src/Benchmarks/Traversers/GridTraversersBenchmark_2D.h

src/Benchmarks/Traversers/GridTraversersBenchmark_3D.h

src/Benchmarks/Traversers/tnl-benchmark-traversers.h