Modify EncodeDateTime() to suppress trailing ".00" in seconds field.  This matches the behavior of the original formatting for abstime. Repair datetime + timespan date arithmetic for year boundaries.  From patch submitted by Dave Skinner.
Modify EncodeDateTime() to suppress trailing ".00" in seconds field.
 This matches the behavior of the original formatting for abstime.
Repair datetime + timespan date arithmetic for year boundaries.
 From patch submitted by Dave Skinner.

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