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

Log Message:
-----------
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.

Modified Files:
--------------
    pgsql/doc/src/sgml:
        config.sgml (r1.76 -> r1.77)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/config.sgml.diff?r1=1.76&r2=1.77)
    pgsql/src/backend/commands:
        portalcmds.c (r1.50 -> r1.51)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/portalcmds.c.diff?r1=1.50&r2=1.51)
        prepare.c (r1.61 -> r1.62)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/prepare.c.diff?r1=1.61&r2=1.62)
    pgsql/src/backend/executor:
        spi.c (r1.158 -> r1.159)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/executor/spi.c.diff?r1=1.158&r2=1.159)
    pgsql/src/backend/tcop:
        postgres.c (r1.499 -> r1.500)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/tcop/postgres.c.diff?r1=1.499&r2=1.500)
    pgsql/src/backend/utils/mmgr:
        portalmem.c (r1.92 -> r1.93)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/mmgr/portalmem.c.diff?r1=1.92&r2=1.93)
    pgsql/src/include/utils:
        portal.h (r1.66 -> r1.67)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/utils/portal.h.diff?r1=1.66&r2=1.67)