Plane detectors, multi-threading support

With this release support for multi-threading support is introduced. To be able to take advantage of this, you will need a geant4 installation that has support enabled. If you have a regular non-multi-threading geant4 installation, this release will run in single thread mode, as before.

Due to changes in the pseudo-random number generators, this version will give a different sequence of events than v1.0.0, but there are no changes to the actual physics, input macro syntax, or output ROOT file structure.