Added coment re. necessary refactoring.

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branch : 1.8
Refactored to use coordinates property.

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branch : 1.8
Added naive tests for DrawingWriter and ShapeWriter.

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branch : 1.8
Add test for handling images and refactor image handling to dedicated method.

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branch : 1.8
Imports moved to module scope.

--HG--
branch : 1.8
Refactored to allow for testing of image writing in isolation. Hacked additional namespace to be well-formed.

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branch : 1.8