Fix class loader when extracting lambdas
Fix various deprecation warnings in tests
[FLINK-1143] Allow delta iterations that do not join with the solution set
[FLINK-1148] Create a writeAsCsv(path, writemode) variant
[FLINK-1152] More robust resource release when tasks are canceled during deployment
Better test error messages when canceling tests fail
JoinHints are passed to the optimizer
Optimizer evaluates join hints from high level apis.
Fix incorrect scheduler test that sometimes produces a deadlock
[scala] Change input of grouped ops from TraversableOnce to Iterator

Iterator is a subclass of TraversableOnce, so it doesn't break existing
code. We can have an Iterator anyways and it provides more functions for
the user.