Add three new observables to the master

SplusSminus
SpinSpinCorrelation_kspace
ChargeChargeCorrelation_kspace.

SDL_QMC_Master/qmc_master.cpp

@@ -132,6 +132,9 @@ static const ObservableProperties propertycache[] =
     {"KondoCloud_X", true, FUNCTION, false, true},
     {"DiagonalGreensfunction_kspace", true, VECTORFUNCTION, true, false},
     {"OffDiagonalGreensfunction_kspace", true, VECTORFUNCTION, true, false},
+    {"SplusSminus", true, VECTORFUNCTION, true, false},
+    {"SpinSpinCorrelation_kspace", true, VECTORFUNCTION, true, false},
+    {"ChargeChargeCorrelation_kspace", true, VECTORFUNCTION, true, false},
 };
 
 static const unsigned int nr_of_known_observables = sizeof(propertycache)/sizeof(ObservableProperties);

common/errordata.h

@@ -88,11 +88,11 @@ public:
         error.resize( error_.size() );
         error=error_;
     }
-    std::valarray<Scalar> get_mean(void)
+    std::valarray<Scalar> get_mean(void) const
     {
         return mean;
     }
-    std::valarray<Scalar> get_error(void)
+    std::valarray<Scalar> get_error(void) const
     {
         return error;
     }