initial commit to hard delete segments
Merge branch 'master' into killsegments

Conflicts:
	merger/src/main/java/com/metamx/druid/merger/coordinator/http/IndexerCoordinatorNode.java
cleaning up some interactions with RTR and workers
updating amazon sdk version
Index service support for early returns and choice of commit semantics.

Task:
- Add TaskCallback to run method (for early returns)

TaskStatus:
- Remove CONTINUED status
- Add segmentsNuked (placeholder for future deletion support)
- Add more builder methods
- Add validations to constructor

TaskStorage:
- Add TaskStorageQueryAdapter, a concrete class that wraps TaskStorages and
  provides various read-only convenience methods
- Add getTask method for benefit of TaskStorageQueryAdapter

TaskQueue:
- Rename "done" to "notify"
- notify is responsible for deciding if we should commit
- Add optional commitRunnable to "notify", which gets called when it's time to commit
- Allow nextTasks and commits to run early (statusCode RUNNING)
- Move getStatus, collapseStatus functionality to TaskStorageQueryAdapter
Merge branch 'killsegments' into task-stuff

Conflicts:
	merger/src/main/java/com/metamx/druid/merger/common/TaskStatus.java
	merger/src/main/java/com/metamx/druid/merger/common/task/DeleteTask.java
	merger/src/main/java/com/metamx/druid/merger/common/task/IndexGeneratorTask.java
	merger/src/main/java/com/metamx/druid/merger/common/task/IndexTask.java
	merger/src/main/java/com/metamx/druid/merger/common/task/MergeTask.java
	merger/src/main/java/com/metamx/druid/merger/coordinator/LocalTaskRunner.java
	merger/src/main/java/com/metamx/druid/merger/coordinator/TaskQueue.java
	merger/src/main/java/com/metamx/druid/merger/coordinator/exec/TaskConsumer.java
	merger/src/main/java/com/metamx/druid/merger/worker/TaskMonitor.java
	merger/src/test/java/com/metamx/druid/merger/coordinator/RemoteTaskRunnerTest.java
	merger/src/test/java/com/metamx/druid/merger/coordinator/TaskQueueTest.java
S3SegmentKiller: Add TODO note
Merge branch 'master' into task-stuff
Index service: Fix kill task
Index service: TaskConsumer tests
RemoteTaskRunner: null check on workerData
fix unit test bug
RemoteTaskRunner: Only cleanup paths during bootstrapping if task is complete
fix worker node still using db connection
Merge branch 'master' of github.com:metamx/druid into task-stuff
TaskStatus: Fix javadocs
Introduce TaskExistsException, thrown by TaskStorage.insert when appropriate
TaskToolbox: Replace IndexerCoordinatorConfig with TaskConfig
TaskStorageQueryAdapter: Rename some methods and tweak javadocs for clarity
TaskGroup: Add javadocs