Added task execution framework
Migrated graph over to new task executor
Added events and task cleanup
Converted tasks to ForkJoin tasks to allow for parallel execution.
Added tests for the log entry iterator
Beginnings of a rebuildable index implementation and associated test.
Finished testing of the EntityVersionCleanupTask
Revert "Converted tasks to ForkJoin tasks to allow for parallel execution."

This reverts commit dc3f448c946219c44e3dbfadb294fea0b8048343.

The ForkJoinPool does not have the following characteristics

Ability to name a pool
Ability to set queue size for rejection

As a result, it is not well suited for our asynchronous I/O tasks, and I'm moving back to ExecutorService

Conflicts:
	stack/corepersistence/collection/src/main/java/org/apache/usergrid/persistence/collection/impl/EntityVersionCleanupTask.java
	stack/corepersistence/common/src/main/java/org/apache/usergrid/persistence/core/task/ImmediateTask.java
	stack/corepersistence/common/src/main/java/org/apache/usergrid/persistence/core/task/NamedTaskExecutorImpl.java
	stack/corepersistence/common/src/main/java/org/apache/usergrid/persistence/core/task/Task.java
	stack/corepersistence/common/src/main/java/org/apache/usergrid/persistence/core/task/TaskExecutor.java
	stack/corepersistence/common/src/test/java/org/apache/usergrid/persistence/core/task/NamedTaskExecutorImplTest.java
	stack/corepersistence/graph/src/main/java/org/apache/usergrid/persistence/graph/serialization/impl/shard/ShardGroupCompaction.java
	stack/corepersistence/graph/src/main/java/org/apache/usergrid/persistence/graph/serialization/impl/shard/impl/ShardGroupCompactionImpl.java
Finished updating back to executor pool
Ignoring tests that are causing build to fail. Needs to be run with external cassandra or manually in Jenkins
Fixes bug with invalid scan range being build on shard scan
Fixes spring configuration of queue listener

Fixes bug where executor pool size is always 1.  Now matches number of threads so that more than 1 task will actually be running.
Fix for BasicIT failure.
Merge branch 'two-dot-o' of https://git-wip-us.apache.org/repos/asf/incubator-usergrid into two-dot-o
Need to support order by boolean too.
Merge branch 'two-dot-o' into eventsystem
Beginning of some new migration methods.
Removed stress tests that should not be part of the build
shorter transaction times; smaller batches
update queue numbers