New release (r3)

Changes for r3:

• slightly smaller text for the UI
• bugfix: the message for the object the user was looking at was not being updated correctly
• the action the user with an object is only shown if they are at the correct distance
• house stair was missing the material
• back door from houses can now be used
• house doors have a probability of being initially locked, instead of always being locked
• not all houses have back doors
• bugfix: inner/outer portcullis levers toggles the nearest portcullis and not ALL of them
• bugfix: portcullis handle was not using the correct materials
• build scripts create a "release.txt" in each new binary with the date and the release number set in Unity