Reimplement NUMERIC datatype using base-10000 arithmetic; also improve

some of the algorithms for higher functions.  I see about a factor of ten
speedup on the 'numeric' regression test, but it's unlikely that that test
is representative of real-world applications.
initdb forced due to change of on-disk representation for NUMERIC.

Author: tglsfdc

doc/src/sgml/release.sgml

@@ -1,5 +1,5 @@
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-$Header: /cvsroot/pgsql/doc/src/sgml/release.sgml,v 1.185 2003/02/05 17:41:32 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/release.sgml,v 1.186 2003/03/21 01:58:04 tgl Exp $
 -->
 
 <appendix id="release">
@@ -24,6 +24,7 @@ CDATA means the content is "SGML-free", so you can write without
 worries about funny characters.
 -->
 <literallayout><![CDATA[
+Reimplementation of NUMERIC datatype for more speed
 New regular expression package, many more regexp features (most of Perl5)
 Can now do EXPLAIN ... EXECUTE to see plan used for a prepared query
 Explicit JOINs no longer constrain query plan, unless JOIN_COLLAPSE_LIMIT = 1