size_x and size_y variables removed

Now size is taked directly from the fill tables. This means that now
fill tables should also be complete (you wont get away with half
tables).
Non-squared shapes working

Fixed a bug where non-square shapes were not working.
Builder for SpriteGenerator

A Builder has been created for the SpriteGenerator, and now instances
are created via the builder. I am not completely satisfied yet as
SpriteGenerator fields are not final and can be modified after creation.