Another round to remove final modifier to private methods because it is not needed

Remove final modifier to private methods because it is not needed.
Those methods are final by default.

Author: Henry Saputra <henry.saputra@gmail.com>

Closes #168 from hsaputra/remove_final_privatemethods_1 and squashes the following commits:

860b512 [Henry Saputra] Remove final modifier to private methods because it is not needed. It is final by default.
[FLINK-1203] Deactivate fork reuse in tests (workaround for potential surefire bug)

This closes #174
[FLINK-1202] Remove incomplete file outputs on failure

This closes #175
Remove obsolete collection execution example.
Correct remote collector format example.
Implement coarse-grained fault tolerance
Introduce a delay before restarts to make sure that taskmanager failures are detected before restart.
Improve error messages in case of invalid file paths or URIs

This closes #170
Make sure TaskManager does not accept task deployments when shutting down
[FLINK-1205] Fix library cache manager to track references to tasks and revent accidental duplicate registration/deregistration
[FLINK-1203] Use forked execution in all tests, except in the end-to-end integration tests in flink-tests
[FLINK-1198] Broadcast variables are shared between tasks in the same TaskManager
[FLINK-1198] Make Broadcast variables shared per taskmanager, rather than a shared singleton per JVM
             (supports multiple TaskManagers in the same JVM)
[FLINK-1198] Broadcast variables can share initialization via broadcast variable initializers
[FLINK-1198] Fix nullpointer exception in broadcast variable materialization
Make sure that operator names are properly escaped for display in the web client
Temporarily disable fork reuse in flink-tests Unit tests (workaround for FLINK-1207)
[doc] Fix programming guide link in iterations.md
[FLINK-1210] Improve error message in delta iterations when the next workset does not depend on the workset
[FLINK-1174] [streaming] Added window join operator
[streaming] Enhanced BufferTimeout functionality for StreamRecordWriter