Log Message:
Update seqdiag to 0.9.3.

0.9.3 (2014-07-03)
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* Fix bugs

0.9.2 (2014-07-02)
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* Change interface of docutils node (for sphinxcontrib module)

0.9.1 (2014-06-23)
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* Add options to blockdiag directive (docutils extension)
   - :width:
   - :height:
   - :scale:
   - :align:
   - :name:
   - :class:
   - :figwidth:
   - :figclass: