Hybrid ALNS

This is an implementation of the Adaptive Large Nighbourhood Search metaheuristic, hybridised with Tabu Search to make it more effective on flat-landscape problems. Early positive results of hybridisation on the Selective Graph Colouring Problem made me believe this could be viable for a wider range of problems. However, I could not manage to produce acceptable results on the classic Vertex Colouring Problem. There is, however, a considerable implementation effort and this code, I believe, could be easily reused for other tasks.