Allow items to be inactive when the game starts
Add fire graphic
Add some fire as an example barrier
Added the ability to have barriers.  Also added back the try/catch block in keyhandler.js because it makes debugging easier.
Allow adding objects to the scenario, in addition to removing them.  Only affects objects that are already in the file but have been removed.
The fire no longer appears until you talk to the person, demonstrating the feature I mentioned in feature/inventory-triggers
Merge pull request #23 from rcatlin/feature/barriers

Feature/barriers