A better tutorial

Rebuilt the tutorial level to make it harder to go off in the "wrong" direction and introduce more gameplay features (gates, fuel pods). Also added some dialog that explains the world and technology a little but I may end up replacing some of that with an opening cutscene.

• Added editor icons for new entities
• Moved tooltip text in editor
• Fixed display issues on integrated graphics
• Added text label to fuel stations
• Fixed fuel pods spawning fully inside walls or structures
• New tutorial level