added get_bbob2009_problem(const int problem_index,...) and a few use-cases to demo.c
added get_bbob2009_problem(const int problem_index,...) and
a few use-cases to demo.c

dtusar/coco,oaelhara/numbbo,oaelhara/numbbo,NDManh/numbbo,dtusar/coco,dtusar/coco,oaelhara/numbbo,oaelhara/numbbo,NDManh/numbbo,NDManh/numbbo,oaelhara/numbbo,dtusar/coco,oaelhara/numbbo,dtusar/coco,NDManh/numbbo,NDManh/numbbo,dtusar/coco,NDManh/numbbo,dtusar/coco,oaelhara/numbbo,NDManh/numbbo,NDManh/numbbo,oaelhara/numbbo,NDManh/numbbo,dtusar/coco,dtusar/coco,oaelhara/numbbo