Add descriptions to TODO items and make adjustments based on 7.5.
Add descriptions to TODO items and make adjustments based on 7.5.

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