[Feature] Basic Inventory Functionality

[ruba1987]

• [x] Inventory screen (the grid to show items)
• [x] Item bar for quick access
• [x] Adding items to the item bar
• [x] Picking up items
• [x] Moving items around in inventory (basic management)
• [x] Dropping items and picking them back up

[ruba1987]

@ProjectRPG/thinktank https://drive.google.com/file/d/0B1dKeBFXLg0rN2RaYUNPdE1iNjA/edit?usp=sharing

Let me know what you think and if you like it and think it meets the goals of this task then I will merge it into master.

[dakdaros]

Yeah, that definitely does everything that's on the checklist. Two thumbs up from me.