python - pq: Add WireMessage and reorder startup packets.

Log Message:
-----------
Add WireMessage and reorder startup packets. Remove the Startup's special string
function as it doesn't need it if type = ''.

Modified Files:
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pq/src:
element3.py (r1.8 -> r1.9)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/pq/src/element3.py.diff?r1=1.8&r2=1.9)