v0.4: Graphing terminals!

Gameplay

• graphing terminals now exist! These allow you to graph in a predefined area rather than just anywhere like before
• the tutorial and the laser level have been updated with graphing terminals in mind, and no longer allow global graphing and tiling
• global graphing and tiling only in the Hub and the Empty level (but still no custom level saving there!)
• new players start off in the tutorial. Once you enter the Hub, you’ll start the game off from there
• most of the tutorial signs have been updated to teach the player a bit better about graphing