SConstruct implemented choose for calculation mode
SWE_DimensionalSplitting approximated the function calculateNumericalFluxes and updateUnkowns to the strukt in swe_simple
and made alternativ funktion to improve performace
swe_simple.cpp included perprozzesor instruktion to use runTimestap instead of calculateNumericalFluxes and updateUnkowns
+some minore fixes and dokumentation
SWE_simple_scemario changes in waterhigh for testing