message: update readme add pointer to files on AliEn
diff: +======== Data directory ==========================
  +The data directory which contained root and text files from GEM scans and MC
  +simulations was moved to tpcdrop on alien:
  +/alice/cern.ch/user/t/tpcdrop/calib/Run3MC/SpaceCharge/TPCupgrade/data
  +
  +So far, these files had not been used
  +
  ======== Continuous readout toy simulation =======
  loadlibs.C //modified version of the one used for GEMtest code. I haven't looked into this so it probably contains a lot of stuff that is not needed
  