Wait for slots instead of TaskManagers in test environment

Instead of waiting for the number of connected task managers, the local
mini cluster used for tests now waits for the total number of available
slots. Waiting for the number of connected task managers instead of the
available slots might result in races in rare situations.

In addition, rename task tracker (sic) to task manager in test classes.
[FLINK-1111] Move Basic and Array Type Information into "flink-core" Project
Fixes for LICENSE and DEPENDENCIES files
Add a FAQ entry about serializability errors
Improved robustness of ExecutionGraphDeploymentTest
[FLINK-1111] Adjust Java-8-tests for type information refactoring
Changed scala copyright header.
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()