bizgres - bizgres: Added the support for multi-column bitmap indexes,

Log Message:
-----------
Added the support for multi-column bitmap indexes, and fixed bugs on maintaining bitmap indexes for update/delete/vacuum operations.

Modified Files:
--------------
bizgres/postgresql/src/backend/access/bitmap:
bitmap.c (r1.6 -> r1.7)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/bizgres/bizgres/postgresql/src/backend/access/bitmap/bitmap.c.diff?r1=1.6&r2=1.7)
bitmapattutil.c (r1.5 -> r1.6)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/bizgres/bizgres/postgresql/src/backend/access/bitmap/bitmapattutil.c.diff?r1=1.5&r2=1.6)
bitmapinsert.c (r1.6 -> r1.7)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/bizgres/bizgres/postgresql/src/backend/access/bitmap/bitmapinsert.c.diff?r1=1.6&r2=1.7)
bitmappages.c (r1.5 -> r1.6)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/bizgres/bizgres/postgresql/src/backend/access/bitmap/bitmappages.c.diff?r1=1.5&r2=1.6)
bitmapsearch.c (r1.3 -> r1.4)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/bizgres/bizgres/postgresql/src/backend/access/bitmap/bitmapsearch.c.diff?r1=1.3&r2=1.4)
bitmaputil.c (r1.6 -> r1.7)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/bizgres/bizgres/postgresql/src/backend/access/bitmap/bitmaputil.c.diff?r1=1.6&r2=1.7)
bitmapxlog.c (r1.5 -> r1.6)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/bizgres/bizgres/postgresql/src/backend/access/bitmap/bitmapxlog.c.diff?r1=1.5&r2=1.6)
bizgres/postgresql/src/backend/executor:
nodeBitmapAnd.c (r1.4 -> r1.5)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/bizgres/bizgres/postgresql/src/backend/executor/nodeBitmapAnd.c.diff?r1=1.4&r2=1.5)
nodeBitmapHeapscan.c (r1.4 -> r1.5)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/bizgres/bizgres/postgresql/src/backend/executor/nodeBitmapHeapscan.c.diff?r1=1.4&r2=1.5)
nodeBitmapIndexscan.c (r1.4 -> r1.5)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/bizgres/bizgres/postgresql/src/backend/executor/nodeBitmapIndexscan.c.diff?r1=1.4&r2=1.5)
nodeBitmapOr.c (r1.4 -> r1.5)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/bizgres/bizgres/postgresql/src/backend/executor/nodeBitmapOr.c.diff?r1=1.4&r2=1.5)
bizgres/postgresql/src/backend/nodes:
ondiskbitmapwords.c (r1.2 -> r1.3)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/bizgres/bizgres/postgresql/src/backend/nodes/ondiskbitmapwords.c.diff?r1=1.2&r2=1.3)
bizgres/postgresql/src/include/access:
bitmap.h (r1.6 -> r1.7)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/bizgres/bizgres/postgresql/src/include/access/bitmap.h.diff?r1=1.6&r2=1.7)
bizgres/postgresql/src/include/nodes:
execnodes.h (r1.5 -> r1.6)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/bizgres/bizgres/postgresql/src/include/nodes/execnodes.h.diff?r1=1.5&r2=1.6)
ondiskbitmapwords.h (r1.2 -> r1.3)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/bizgres/bizgres/postgresql/src/include/nodes/ondiskbitmapwords.h.diff?r1=1.2&r2=1.3)