Add Joe's table functions description.
Add Joe's table functions description.

Chibin/gpdb,ahachete/gpdb,xuegang/gpdb,foyzur/gpdb,0x0FFF/gpdb,Quikling/gpdb,adam8157/gpdb,xuegang/gpdb,janebeckman/gpdb,Chibin/gpdb,zeroae/postgres-xl,randomtask1155/gpdb,ashwinstar/gpdb,adam8157/gpdb,50wu/gpdb,rubikloud/gpdb,edespino/gpdb,edespino/gpdb,yuanzhao/gpdb,Postgres-XL/Postgres-XL,randomtask1155/gpdb,CraigHarris/gpdb,yuanzhao/gpdb,Quikling/gpdb,arcivanov/postgres-xl,xinzweb/gpdb,royc1/gpdb,CraigHarris/gpdb,rvs/gpdb,lpetrov-pivotal/gpdb,kaknikhil/gpdb,foyzur/gpdb,oberstet/postgres-xl,Quikling/gpdb,randomtask1155/gpdb,atris/gpdb,Chibin/gpdb,chrishajas/gpdb,zeroae/postgres-xl,lintzc/gpdb,xinzweb/gpdb,janebeckman/gpdb,yuanzhao/gpdb,greenplum-db/gpdb,foyzur/gpdb,Quikling/gpdb,kaknikhil/gpdb,CraigHarris/gpdb,lisakowen/gpdb,Postgres-XL/Postgres-XL,Quikling/gpdb,kaknikhil/gpdb,ovr/postgres-xl,edespino/gpdb,zaksoup/gpdb,edespino/gpdb,lintzc/gpdb,kmjungersen/PostgresXL,tpostgres-projects/tPostgres,zaksoup/gpdb,50wu/gpdb,lpetrov-pivotal/gpdb,rubikloud/gpdb,ashwinstar/gpdb,rvs/gpdb,tangp3/gpdb,50wu/gpdb,jmcatamney/gpdb,jmcatamney/gpdb,rvs/gpdb,ahachete/gpdb,rvs/gpdb,0x0FFF/gpdb,cjcjameson/gpdb,zaksoup/gpdb,50wu/gpdb,randomtask1155/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,royc1/gpdb,rvs/gpdb,cjcjameson/gpdb,Chibin/gpdb,cjcjameson/gpdb,postmind-net/postgres-xl,lisakowen/gpdb,snaga/postgres-xl,ovr/postgres-xl,snaga/postgres-xl,ovr/postgres-xl,lpetrov-pivotal/gpdb,ashwinstar/gpdb,royc1/gpdb,janebeckman/gpdb,pavanvd/postgres-xl,arcivanov/postgres-xl,kaknikhil/gpdb,lisakowen/gpdb,tpostgres-projects/tPostgres,kmjungersen/PostgresXL,Quikling/gpdb,zaksoup/gpdb,cjcjameson/gpdb,lpetrov-pivotal/gpdb,xinzweb/gpdb,tangp3/gpdb,royc1/gpdb,kaknikhil/gpdb,edespino/gpdb,50wu/gpdb,Postgres-XL/Postgres-XL,pavanvd/postgres-xl,zeroae/postgres-xl,rubikloud/gpdb,lisakowen/gpdb,lintzc/gpdb,rubikloud/gpdb,0x0FFF/gpdb,janebeckman/gpdb,royc1/gpdb,lpetrov-pivotal/gpdb,tangp3/gpdb,lisakowen/gpdb,xinzweb/gpdb,jmcatamney/gpdb,foyzur/gpdb,postmind-net/postgres-xl,ashwinstar/gpdb,Quikling/gpdb,CraigHarris/gpdb,royc1/gpdb,xuegang/gpdb,techdragon/Postgres-XL,pavanvd/postgres-xl,lisakowen/gpdb,randomtask1155/gpdb,jmcatamney/gpdb,CraigHarris/gpdb,edespino/gpdb,royc1/gpdb,kmjungersen/PostgresXL,yazun/postgres-xl,janebeckman/gpdb,adam8157/gpdb,postmind-net/postgres-xl,yazun/postgres-xl,cjcjameson/gpdb,xuegang/gpdb,chrishajas/gpdb,tangp3/gpdb,atris/gpdb,lpetrov-pivotal/gpdb,ahachete/gpdb,xinzweb/gpdb,Chibin/gpdb,zaksoup/gpdb,postmind-net/postgres-xl,ahachete/gpdb,chrishajas/gpdb,Postgres-XL/Postgres-XL,janebeckman/gpdb,pavanvd/postgres-xl,rubikloud/gpdb,chrishajas/gpdb,kaknikhil/gpdb,Chibin/gpdb,edespino/gpdb,greenplum-db/gpdb,kaknikhil/gpdb,rvs/gpdb,Chibin/gpdb,oberstet/postgres-xl,techdragon/Postgres-XL,Chibin/gpdb,foyzur/gpdb,0x0FFF/gpdb,Chibin/gpdb,50wu/gpdb,techdragon/Postgres-XL,ovr/postgres-xl,randomtask1155/gpdb,arcivanov/postgres-xl,royc1/gpdb,adam8157/gpdb,oberstet/postgres-xl,greenplum-db/gpdb,ashwinstar/gpdb,0x0FFF/gpdb,jmcatamney/gpdb,chrishajas/gpdb,janebeckman/gpdb,chrishajas/gpdb,snaga/postgres-xl,kmjungersen/PostgresXL,tpostgres-projects/tPostgres,ashwinstar/gpdb,tangp3/gpdb,rvs/gpdb,lintzc/gpdb,rubikloud/gpdb,postmind-net/postgres-xl,janebeckman/gpdb,randomtask1155/gpdb,lintzc/gpdb,atris/gpdb,adam8157/gpdb,yuanzhao/gpdb,arcivanov/postgres-xl,CraigHarris/gpdb,janebeckman/gpdb,Quikling/gpdb,atris/gpdb,tangp3/gpdb,arcivanov/postgres-xl,xuegang/gpdb,jmcatamney/gpdb,yuanzhao/gpdb,randomtask1155/gpdb,0x0FFF/gpdb,edespino/gpdb,greenplum-db/gpdb,xuegang/gpdb,cjcjameson/gpdb,janebeckman/gpdb,ahachete/gpdb,ashwinstar/gpdb,tangp3/gpdb,yuanzhao/gpdb,Chibin/gpdb,zaksoup/gpdb,ahachete/gpdb,xuegang/gpdb,yazun/postgres-xl,lintzc/gpdb,yuanzhao/gpdb,atris/gpdb,Postgres-XL/Postgres-XL,adam8157/gpdb,yuanzhao/gpdb,zeroae/postgres-xl,edespino/gpdb,greenplum-db/gpdb,xuegang/gpdb,kaknikhil/gpdb,xinzweb/gpdb,snaga/postgres-xl,cjcjameson/gpdb,50wu/gpdb,greenplum-db/gpdb,edespino/gpdb,lisakowen/gpdb,xinzweb/gpdb,kaknikhil/gpdb,pavanvd/postgres-xl,tangp3/gpdb,ovr/postgres-xl,lisakowen/gpdb,50wu/gpdb,rvs/gpdb,techdragon/Postgres-XL,chrishajas/gpdb,zaksoup/gpdb,tpostgres-projects/tPostgres,cjcjameson/gpdb,ashwinstar/gpdb,kmjungersen/PostgresXL,adam8157/gpdb,lpetrov-pivotal/gpdb,zaksoup/gpdb,ahachete/gpdb,adam8157/gpdb,lpetrov-pivotal/gpdb,rubikloud/gpdb,0x0FFF/gpdb,ahachete/gpdb,arcivanov/postgres-xl,atris/gpdb,lintzc/gpdb,rvs/gpdb,yazun/postgres-xl,cjcjameson/gpdb,CraigHarris/gpdb,atris/gpdb,lintzc/gpdb,foyzur/gpdb,CraigHarris/gpdb,atris/gpdb,foyzur/gpdb,Quikling/gpdb,cjcjameson/gpdb,chrishajas/gpdb,oberstet/postgres-xl,rubikloud/gpdb,zeroae/postgres-xl,xuegang/gpdb,snaga/postgres-xl,tpostgres-projects/tPostgres,Quikling/gpdb,yazun/postgres-xl,CraigHarris/gpdb,greenplum-db/gpdb,0x0FFF/gpdb,techdragon/Postgres-XL,oberstet/postgres-xl,foyzur/gpdb,xinzweb/gpdb,yuanzhao/gpdb,jmcatamney/gpdb,lintzc/gpdb,yuanzhao/gpdb,kaknikhil/gpdb,rvs/gpdb