Thread: pgsql-server: Update the in-code documentation about the transaction

Log Message:
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Update the in-code documentation about the transaction system.  Move it
into a README file instead of being in xact.c's header comment.
Alvaro Herrera.

Modified Files:
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    pgsql-server/src/backend/access/transam:
        xact.c (r1.175 -> r1.176)

(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/access/transam/xact.c.diff?r1=1.175&r2=1.176)

Added Files:
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    pgsql-server/src/backend/access/transam:
        README (r1.1)

(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/access/transam/README?rev=1.1&content-type=text/x-cvsweb-markup)