[FLINK-1005] By default, new objects are created for each element in group operations
[FLINK-1214] Prevent partitionings on subsets of fields from being pushed down
Add test case for TaskManager connection loss, leading to task failure.
[FLINK-1220] Promote various log statements to INFO level. Add log statements for assignment locations
Merge branch 'master' of github.com:apache/incubator-flink into FLINK-1218
Fixed TaskManagerLossFailsTasksTest to avoid creating boxed objects