reset rescaling factor to 1.0 even if its zero as given in the CR block (issue #12)

lib/imc_channel.hpp

@@ -394,7 +394,8 @@ namespace imc
         for ( imc::datatype& el: ydata_ )
         {
           //std::cout<<"value:"<<el.as_double()<<"\n";
-          el = imc::datatype(el.as_double()*factor_ + offset_);
+          double fact = ( factor_ == 0.0 ) ? 1.0 : factor_;
+          el = imc::datatype(el.as_double()*fact + offset_);
         }
       }
     }