Port from master in Sim09-upgrade changes in VPMoniSim
Port into Sim09-upgrade branch changes from master that were committed in svn, git-svn-id: svn+ssh://svn.cern.ch/reps/lhcb/Gauss/trunk@207499 4525493e-7705-40b1-a816-d608a930855b
VPGaussMoni.cpp: Fixed MCVertexPosZX plot and added new plot of distance traversed in silicon by Manuel Jahn (Summer Student) and @mrwillia
- Edit VPGaussMoni.cpp to fix MCVertexPosZX (was plotting ZY)
- Add new plot showing distance traversed in silicon (SiDist)