upgrade to Jackson 2.3.0
upgrade to latest jsr166
Enable incremental compilation using a workaround for the maven-compiler-plugin 3.1 bug
Resolve potential deadlock state during EsThreadPoolExecutor shutdown

Fixes #4334

The deadlock occurs between monitor object of EsThreadPoolExecutor and mainLock of ThreadPoolExecutor. The shutdown method of EsThreadPoolExecutor obtains the lock on monitor first and waits for mainLock of ThreadPoolExecutor in ThreadPoolExecutor#shutdown for part of the processing, while EsThreadPoolExecutor#terminated is executed under mainLock and tries to obtain monitor to notify listeners.
Update minimum_master_nodes comment to match documentation

Someone on the mailing list wrongly interpreted it to mean the current node is not included in the calculation.
Fix QuorumLocalGatewayTests#testChangeInitialShardsRecovery to start only one shard to not fulfill the quorum
wait until cluster-state is ready after startup
Increased timeout in ClusterServiceTests.testTimeoutUpdateTask to 100ms

The previous 2ms timeout was too small and caused a racing condition in timeout handling. This will be fixed but requires more work.
Cat API: Add endpoint to show aliases

This endpoint allows to check aliases, their indices, if a filter is
configured along with routing values for searching and indexing.

Closes #4414
Optimizes performance of AllocationDecider execution. Instead of using loops over all ShardRoutings, do accounting in RoutingNodes.
Speeds up recalculating cluster state on large clusters.
Improve RoutingNodes API

Currently the RoutingNodes API allows modification of it's internal state outside of the class.
This commit improves the APIs of `RoutingNode` and `RoutingNode` to change internal state
only within the classes itself.

Closes #4458
Reset source shards to `started` if canceling relocation.

Currently we miss to reset the source shards status to ACTIVE if we cancel
a relocation. If the shard is RELOCATING we need to reset to state ACTIVE.

Closes #4457
Added new IndicesLifecycle.Listener method that allows to listen for any IndexShardState internal change.

Closes #4413