pgsql: Update the tznames reference files, and add IDT (Israel Daylight

Log Message:
-----------
Update the tznames reference files, and add IDT (Israel Daylight Time)
to the Default timezone abbreviation set.

Back-port the the current file set to all branches that contain tznames.
This includes adding SGT to the Default set in pre-8.4 releases.

Joachim Wieland

Modified Files:
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    pgsql/src/timezone/tznames:
        Africa.txt (r1.2 -> r1.3)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/timezone/tznames/Africa.txt?r1=1.2&r2=1.3)
        Asia.txt (r1.3 -> r1.4)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/timezone/tznames/Asia.txt?r1=1.3&r2=1.4)
        Australia.txt (r1.2 -> r1.3)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/timezone/tznames/Australia.txt?r1=1.2&r2=1.3)
        Default (r1.7 -> r1.8)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/timezone/tznames/Default?r1=1.7&r2=1.8)
        Europe.txt (r1.2 -> r1.3)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/timezone/tznames/Europe.txt?r1=1.2&r2=1.3)
        README (r1.3 -> r1.4)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/timezone/tznames/README?r1=1.3&r2=1.4)