#2232
Introduced ILocalImprovementAlgorithmOperator to separate single operators for local improvement and operator graphs/algorithms for local improvement.
This way the ILocalImprovementOperator does not have to specify a problem type and does not store a problem any more.
The LocalSearchImprovementOperator and SimulatedAnnealingImprovementOperator implement the new ILocalImprovementAlgorithmOperator as they represent an operator graph for local improvement.
The QAP and VRP local improvement operators implement the ILocalImprovementOperator which does not store a problem anymore.
