Changed scala copyright header.
Merge branch 'master' of https://github.com/apache/incubator-flink
Updated license notices in in java files to be written in block comments instead of javadoc comments.
[FLINK-1114] Move scala-style checks to scala projects, change paths to style conifg, to allow isolated building of individual projects.
[FLINK-1115] Local file streams retry file creation on FileNotFoundException to increase resilience against spurious failures in tests
Improve error message when scheduler cannot find a slot for immediate scheduling.
Improve robustness of task manager test
Remove error message in execution graph for concurrent state changes that are fully acceptable.
Tasks are marked correctly as failed (not canceled), when the taskmanager kills then during shutdown or reset.
Limit number of RPC worker threads in TaskManager to prevent OutOfMemory (thread space) errors
[FLINK-1077] Fix unstable test CliFrontendPackageProgramTest
[FLINK-1119] Make sure test mini cluster has started properly before submitting the test job.
[FLINK-1060] Added methods to DataSet to explicitly hash-partition or rebalance the input of Map-based operators.

This closes #108
Exclude DataSet.rebalance() and DataSet.partitionByHash() methods from ScalaAPICompletenessTest
Added documentation for rebalance() and partitionByHash()
[FLINK-1073] Added test case to reproduce error
[FLINK-1073] Enables sorted group input for GroupReduce combiners.
- GroupReduceCombineDriver uses separate comparators for sorting and grouping.
- Adding support for multiple comparators for a single input driver required some refactoring.

This closes #109
[FLINK-970] Adds first() operation on DataSet, UnsortedGrouping, and SortedGrouping

This closes #88
Merge branch 'master' of https://github.com/apache/incubator-flink
Added parameter checks and tests for first-n operator.
Excluded DataSet.first(), UnsortedGrouping.first(), and SortedGrouping.first() methods from ScalaAPICompletenessTest.