Optimization: Fix bug in ObjectiveChecker and ObjectiveChecker1D

* Bug caused the checks to be run every time a value/gradient/hessian was
requested, not just the first time a request was made.

(updated by cdrnet)

src/Numerics/Optimization/ObjectiveChecker.cs

@@ -73,6 +73,7 @@ namespace MathNet.Numerics.Optimization
                         throw new EvaluationException("Objective function evaluation failed.", InnerEvaluation, e);
                     }
                     Checker.ValueChecker(InnerEvaluation);
+					ValueChecked = true;
                 }
                 return InnerEvaluation.Value;
             }
@@ -94,6 +95,7 @@ namespace MathNet.Numerics.Optimization
                         throw new EvaluationException("Objective gradient evaluation failed.", InnerEvaluation, e);
                     }
                     Checker.GradientChecker(InnerEvaluation);
+					GradientChecked = true;
                 }
                 return InnerEvaluation.Gradient;
             }
@@ -115,6 +117,7 @@ namespace MathNet.Numerics.Optimization
                         throw new EvaluationException("Objective hessian evaluation failed.", InnerEvaluation, e);
                     }
                     Checker.HessianChecker(InnerEvaluation);
+					HessianChecked = true;
                 }
                 return InnerEvaluation.Hessian;
             }

src/Numerics/Optimization/ObjectiveChecker1D.cs

@@ -72,6 +72,7 @@ namespace MathNet.Numerics.Optimization
                         throw new EvaluationException("Objective function evaluation failed.", InnerEvaluation, e);
                     }
                     Checker.ValueChecker(InnerEvaluation);
+					ValueChecked = true;
                 }
                 return InnerEvaluation.Value;
             }
@@ -93,6 +94,7 @@ namespace MathNet.Numerics.Optimization
                         throw new EvaluationException("Objective derivative evaluation failed.", InnerEvaluation, e);
                     }
                     Checker.DerivativeChecker(InnerEvaluation);
+					DerivativeChecked = true;
                 }
                 return InnerEvaluation.Derivative;
             }
@@ -114,6 +116,7 @@ namespace MathNet.Numerics.Optimization
                         throw new EvaluationException("Objective second derivative evaluation failed.", InnerEvaluation, e);
                     }
                     Checker.SecondDerivativeChecker(InnerEvaluation);
+					SecondDerivativeChecked = true;
                 }
                 return InnerEvaluation.SecondDerivative;
             }