change Laplace_SOT to Simple_SOT in tutorial

doc/tutorial/ellipt.tex

@@ -189,7 +189,7 @@ The operators now are defined as follows:
 \begin{lstlisting}{}
   // ===== create matrix operator =====
   Operator matrixOperator(ellipt.getFeSpace());
-  matrixOperator.addSecondOrderTerm(new Laplace_SOT);
+  matrixOperator.addSecondOrderTerm(new Simple_SOT);
   ellipt.addMatrixOperator(matrixOperator, 0, 0);
 
   // ===== create rhs operator =====
@@ -201,7 +201,7 @@ The operators now are defined as follows:
 We define a matrix operator (left hand side operator) on the finite
 element space of the problem. The term $-\Delta u$ is added to
 it. Note that the minus sign isn't explicitly given, but implicitly
-contained in \verb+Laplace_SOT+. With \verb+addMatrixOperator+ we add
+contained in \verb+Simple_SOT+. With \verb+addMatrixOperator+ we add
 the operator to the stationary problem definition. The both zeros
 represent the position of the operator in the operator matrix. As we
 are about to define a scalar equation, there is only the 0/0 position

doc/tutorial/heat.tex

@@ -307,7 +307,7 @@ Now, we define the operators:
 
   // create laplace
   Operator A(heatSpace.getFeSpace());
-  A.addSecondOrderTerm(new Laplace_SOT);
+  A.addSecondOrderTerm(new Simple_SOT);
   A.setUhOld(heat.getOldSolution(0));
   if (*(heat.getThetaPtr()) != 0.0)
     heatSpace.addMatrixOperator(A, 0, 0, heat.getThetaPtr(), &one);

doc/tutorial/vecellipt.tex

@@ -80,7 +80,7 @@ The operator definitions for the first equation are:
 \begin{lstlisting}{}
   // ===== create operators =====
   Operator matrixOperator00(vecellipt.getFeSpace(0), vecellipt.getFeSpace(0));
-  matrixOperator00.addSecondOrderTerm(new Laplace_SOT);
+  matrixOperator00.addSecondOrderTerm(new Simple_SOT);
   vecellipt.addMatrixOperator(&matrixOperator00, 0, 0);
 
   int degree = vecellipt.getFeSpace(0)->getBasisFcts()->getDegree();