pgsql: Update release notes for releases 9.0.1, 8.4.5, 8.3.12, 8.2.18,

Update release notes for releases 9.0.1, 8.4.5, 8.3.12, 8.2.18, 8.1.22,
8.0.26, and 7.4.30.

Branch
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master

Details
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http://git.postgresql.org/gitweb?p=postgresql.git;a=commitdiff;h=a5683ea0423752cca323e528cb160273ad794054

Modified Files
--------------
doc/src/sgml/release-7.4.sgml | 97 ++++++++
doc/src/sgml/release-8.0.sgml | 167 ++++++++++++++
doc/src/sgml/release-8.1.sgml | 181 +++++++++++++++
doc/src/sgml/release-8.2.sgml | 249 +++++++++++++++++++++
doc/src/sgml/release-8.3.sgml | 326 +++++++++++++++++++++++++++
doc/src/sgml/release-8.4.sgml | 485 +++++++++++++++++++++++++++++++++++++++++
doc/src/sgml/release-9.0.sgml | 105 +++++++++
7 files changed, 1610 insertions(+), 0 deletions(-)