Removed class GameWindow.
Not flexible enough.
Removed friend classes to class Texture.
But moved a constructor to be public instead of private to compensate this change.
Added error message to SoundBuffer.
Changed in soundbuffer map O(log(n)) to a hash O(1).
And increased code readability.
Added new class used to initiate SoundBuffer.
Changed class Window's inteface for the quiting function.
Removed virtual destuctors in init classes.
They is now protected instead.
Updates code layout to be more eye pleasing.