Come back at home, lxplus

Modified some Boost dependencies, to be able to easily compile on lxplus. In particular, Boost is no more required in the custom dictionary compiled with rootcling: to set the layers, the Boost config file is now read in the TFRGeometry only (which is not compiled as dictionary), instead of in the TFRLayer (which is dictionared).

Temporarily, the TFRSensor type is removed and replace by a simple string. Maybe later I will write a complete class for it.