Now bind displays prepare as detail, and execute displays prepare and

Now bind displays prepare as detail, and execute displays prepare and
optionally bind.  I re-added the "statement:" label so people will
understand why the line is being printed (it is log_*statement
behavior).

Use single quotes for bind values, instead of double quotes, and double
literal single quotes in bind values (and document that).  I also made
use of the DETAIL line to have much cleaner output.