Changed 'Ship' Class Content Management

Originally the texture2D used by ship were loaded inside: 'Map' and
passed into the ship class via the constructor...
I found a better way to do this. And that was to pass the
'Game.ContentManager' itself into the 'Ship' class.
This allows the 'Ship' class itself to load its own content from the
content pipeline.
For example: Content.Load<Texture2D>("EmptyColorMe");