Garbage recollection + recycling + multiobjective

Each Harvester now:
1) Collects the garbage from a building
2) Recycles the garbage in order to maximize the points
3) Stores a stack with all the winning bids (the objectives to reach)
* Time to think reduced in order to have a faster simulation
**AUCTION NOT TESTED WITH MORE HARVESTERS SINCE COLLISIONS DOES NOT WORK

Closes #25