Minor bugfix: chat display with low messages stack
Add inventory and ability to pick up items

* Inventory can be accessed by pressing "i", just a chat message for
now, to become a screen later
* Items can be picked up by standing on the top of the item and pressing
key ",". Items stack in the inventory
* Items now have new flag - "stationary". Makes me rethink objects
separation - might require refactoring.

Minor:
* Map change to add few dummy items