* Replaced calls to Gdx.graphics.getWidth/Gdx.graphics.getHeight methods to static methods SkyMagGame.getWidth/SkyMagGame.getHeight accessing SkyMagGame static attributes.
* Made Ship class abstract, and created DiscShip concrete class inheriting it
* Made changes to touchDragged method in InputHandler.java that might solve the multi-touch bug
Merge pull request #3 from newfelMessouci/master

* Replaced calls to Gdx.graphics.getWidth/Gdx.graphics.getHeight methods to static methods SkyMagGame.getWidth/SkyMagGame.getHeight accessing SkyMagGame static attributes.

    Made Ship class abstract, and created DiscShip concrete class inheriting it
    Made changes to touchDragged method in InputHandler.java that might solve the multi-touch bug