Tip: if you don't specify bounds (or specify empty bounds, I forget which), the game will use a circular collision area based on the collisionRadius.
As to the coordinate system, I forget exactly what it is
It's x,y w/ the ship facing to the right (i.e. towards 0 degrees). The origin might be at the middle of the sprite, or at the rotation center of the ship.
As you might have guessed, there is a ship editor (which is the reason I don't have to remember this anymore). It's not quite ready for prime time, but at some point we'll polish it up and release it.