[diagrams] #15: Fix Ellipse module

[diagrams]

#15: Fix Ellipse module
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 Reporter:  byorgey  |       Owner:     
     Type:  defect   |      Status:  new
 Priority:  major    |   Milestone:  0.3
Component:  lib      |     Version:     
 Keywords:           |  
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 The change back to a linear map + translation representation of affine
 transformations (from a projective representation) means that the Ellipse
 module is now broken, since it depended on the internals of how
 transformations were being represented.  However, I think this also
 represents an opportunity to considerably shorten the Ellipse code since
 it seems that part of what it was doing before was manually computing the
 transpose matrix of the transformation, whereas now the transpose of
 transformations is available directly.

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Ticket URL: <http://trac.haskell.org/diagrams/ticket/15>
diagrams <http://code.haskell.org/diagrams/>
Embedded domain-specific library for describing and rendering diagrams, illustrations, and other graphics.