Use _r for all real_t literals

apps/benchmarks/ComplexGeometry/ComplexGeometry.cpp

apps/benchmarks/CouetteFlow/CouetteFlow.cpp

...arPlaneInShearFlow/ForcesOnSphereNearPlaneInShearFlow.cpp

...marks/MotionSingleHeavySphere/MotionSingleHeavySphere.cpp

apps/benchmarks/NonUniformGrid/NonUniformGrid.cpp

apps/benchmarks/PoiseuilleChannel/PoiseuilleChannel.cpp

apps/benchmarks/SchaeferTurek/SchaeferTurek.cpp

apps/benchmarks/UniformGrid/UniformGrid.cpp

...ases/BidisperseFluidizedBed/BidisperseFluidizedBedDPM.cpp

apps/tools/povrayFileCompressor/main.cpp

apps/tutorials/cuda/01_GameOfLife_cuda.cpp

apps/tutorials/lbm/01_BasicLBM.cpp

apps/tutorials/lbm/02_BasicLBM_ExemplaryExtensions.cpp

apps/tutorials/pe/01_ConfinedGas.cpp

apps/tutorials/pe/02_ConfinedGasExtended.cpp

src/blockforest/BlockForestEvaluation.cpp

src/blockforest/GlobalLoadBalancing.h

src/blockforest/Initialization.cpp

src/blockforest/SetupBlockForest.cpp

src/blockforest/SetupBlockForest.h