Implemented Offers only have one dictionary with pos/neg being both offered and requested, respectively.

 - New GetOfferProposals in Agent & added ConvertAgentProposals to better ensure agents can't do things they are not allowed to do.
 - RandomAgent changed to accomodate
 - Changed availableResources in GameState to use Enum.GetValues
Merge branch 'master' of https://github.com/Oragada/ModernAIProject

Conflicts:
	AITradingProject/AITradingProjectModel/Model/GameState.cs
FairTradeAgent updated