Fixed unexpected crashes in shelves
Added method to perform a lookup in a shelf's inventory
Added function to check whole inventory of a shelf for available ordered pieces
Added position sending from Shelf to Picker
Added shelf initialization of specific Inventory via external arguments
Fixed Console Printings for Shelf -> Picker communication
Added reminders of what to do next (Shelf-wise)
Added conversation between Picker and Shelfs for Shelf selection
Added selection of closest shelf with enough resources by minimum distance =)
Merge remote-tracking branch 'upstream/master'