implements a second passive scalar

src/GksGpu/Analyzer/ConvergenceAnalyzer.cpp

src/GksGpu/Analyzer/TurbulenceAnalyzer.cu

src/GksGpu/BoundaryConditions/AdiabaticWall.cu

src/GksGpu/BoundaryConditions/Inflow.cu

src/GksGpu/BoundaryConditions/Inflow.h

src/GksGpu/BoundaryConditions/IsothermalWall.cu

src/GksGpu/BoundaryConditions/IsothermalWall.h

src/GksGpu/BoundaryConditions/Periodic.cu

src/GksGpu/BoundaryConditions/Pressure.cu

src/GksGpu/BoundaryConditions/SalinasVazquez.cu

src/GksGpu/CellUpdate/CellUpdate.cu

src/GksGpu/Communication/Communicator.cu

src/GksGpu/Definitions/MemoryAccessPattern.h

src/GksGpu/Definitions/PassiveScalar.h

src/GksGpu/FlowStateData/AccessDeviceData.cuh

src/GksGpu/FlowStateData/FlowStateData.cuh

src/GksGpu/FluxComputation/ApplyFlux.cuh

src/GksGpu/FluxComputation/AssembleFlux.cuh

src/GksGpu/FluxComputation/ExpansionCoefficients.cuh

src/GksGpu/FluxComputation/Reconstruction.cuh