[pgScript patch] Output + bug fix

Hi pgAdmin hackers,

Here is a patch for pgAdmin. I have finally completed the patch for
the pgScript outputs and am sorry for the delay.
This patch also corrects a bug in pgsPrintStmt.cpp because of a thread
double lock in case of exception.
I have other updates to send but I would like this one to be committed first.

I have noticed while making this patch that the
pgQueryThread::GetMessagesAndClear() method does not return anything
when my query returns a warning. It did before.
The line 185 is:
  conn->SetLastResultError(NULL);
Before, it was:
  appendMessage(conn->GetLastError() + wxT("\n"));
When I put this line back to what it was, I do not have the problem
anymore. Is this a problem or is there another way to get the last
warning message?

Best regards,
Mickael