SSS Stage1

New enemy ship, it looks great.

Bullet level 1. New bullet and bomb icon.

Added a new muzzle fire effect.
Test : enemy ships move along a path.


- Added stage1 intro and background music.
- Added achievement button.
- Added when attack key is down, ship will do charged attack.
- Added normal bullets lv1 ~ lv5.
- Added muzzle fire.
- Changed stage1 background objects.
- Changed old enemy ship removed.
- Fixed set control keys can't save.
- Fixed ship's movement and control bugs.
- Fixed ship's collision detection.