Replaced doubles by Reals, fixed two bugs

Replaced doubles by Reals, fixed two bugs

* Replaced all doubles by Reals where necessary
* Replaced constructor
    TFactor<T>::TFactor( const VarSet& vars, TIterator begin )
  by two constructors
    TFactor<T>::TFactor( const VarSet& vars, const T* p )
    TFactor<T>::TFactor( const VarSet& vars, const std::vector<S> &x )
* Fixed bugs (min and max were reversed) in
    TFactor<T> min( const TFactor<T> &, const TFactor<T> & )
    TFactor<T> max( const TFactor<T> &, const TFactor<T> & )