Update of the multi hit function in the SimR class and fix of the bethe-bloch calculation for backscattered particles
requested to merge ebechtel_AT_ikf.uni-frankfurt.de/cbmroot:trdReworkSpadicClass into trdReworkSpadicClass
The "CheckMulti" function was completely restructured for better readability and some small fixes were introduced for the introduction of the SPADIC class. The functionality stays the same. A minor change was done in the CbmTrdDigitizer to ensure correct flushing of the R modules in the finish function. A fix was introduced for the calculation of ionizations with the bethe-bloch calculation for backscattered particles.