v0.02 bug fixes and improvements

Some bug fixes and gameplay improvements.

• Added path finding
• Building placement now checks if place is empty
• Unoccupied buildings will show its status
• H button will now focus on main building
• Camera will not go out of game area
• Camera will stop moving if game window loses focus or outside of game window for sometime
• Limited the number of enemies and changed its pattern
• Added win condition when all enemies are defeated

Known bugs;

• Sometimes new units spawns on top of each other and will go out of screen if you try to move them