In copyEdgeNodes the nodes were copied to the wrong places of the send vector. The problem was that the full vector sendProcessNeighborHostAllNodes was used for copying instead of the shorter vector sendProcessNeighborHostAfterFtoC

SetRecvFsPostDev27() is now called after communication in all directions is finished. This is needed for communication hiding, when cutting the domain in multiple directions.

Avoid calling method to find neighborNodes in every timestep

also rename methods exchangePostCollDataGPU27() to exchangeCollDataGPU27()

prevents accidental use of the null stream

* move cudaEventRecord to UpdateGrid27
* use variables for stream indices in UpdateGrid27
* create and destroy streams in Simulation.init() and Simulation.free()

Previously, the event was also triggered when data was written. This behavior caused crashes of VF