Bug fixes and improvements

• The terrain has been adjusted and is now more detailed.
• The terrain textures have been adjusted.
• The bug where the camera would freeze when hovering over the building buttons with the mouse has been fixed.
• The camera can no longer fly through mountains.
• Two additional tree types have been added, which spawn when the game starts.
• The UI in the main menu has been adjusted.
• The orange and blue buildings had visual bugs with the windows and bushes, which have been fixed.