Spaceship control improvement

[luddchen]

• deceleration only down to zero; backwards need separate keystroke
• Yaw combined with Roll (similar to airplane movement)
• fire Laser alternately from both sides of the ship
• integrate laser heat system

[luddchen]

done :

• alternate laser fire position
• Acceleration/Deceleration stops at zero until key is released moved to new Issue :
• laser heat system
• flight physics