Post-jam update 1

What's new:

• We've replaced level 3 with a different level since it was too easy to beat by blocking narrow paths with rocks/trees. We might add it back later if we add mechanics that can render this sort of play infeasible.
• Added support for multiple work areas.
• Increased gun turret damage from 1.5 to 2, decrease laser turret damage from 2 to 1.
• Laser beams are destroyed if they hit 3 enemies.
• Simplified input: just press the beam button to select blueprint.
• On the menu screen you can select a level by pressing its number on the keyboard.
• Refactored input handling in order to prepare for adding local multiplayer ;)