Action relaxation

Same as previous pull request (from KnowledgebaseTools) and added:
 - Relaxed mix action
 - Relaxed pour action
 - Making more comprehensive mashed potatoes recipe
 - Basic kitchen now keeps track of completed subgoals and (can) update the server accordingly.
 - Bug squashing!  
 - updated testing suite
You should just do an intersection of two sets here. Look at the retainAll method