Allow COPY to use parameters

Folks,

Per discussion on IRC and some test code, COPY can't take parameters
in a PREPARE, which feature would make it even more useful.  To make
this work, we'd need to:

- do parse analysis immediately
- parameterize all the options

This doesn't seem like a gigantic lift.  What say?

Cheers,
David.
-- 
David Fetter <david@fetter.org> http://fetter.org/
Phone: +1 415 235 3778  AIM: dfetter666  Yahoo!: dfetter
Skype: davidfetter      XMPP: david.fetter@gmail.com

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