[Test] testHostOnMessages - only decrease latch after setting transport addresses
[TEST] wait for green before deleting mapping
[TEST] wait for green before deleting mapping
Snapshot/Restore: Add ability to restore indices without their aliases

Closes #6457
Core: Added missing return statements.

Closes #6841
[Test] renamed testListenerCallbacks to testLocalNodeMasterListenerCallbacks

Also clean up internal variable namings and fixed usage of wrong setting causing last node to not use the min_master_node settings.
[Test] one more tweak to testLocalNodeMasterListenerCallbacks
[RECOVERY] Increment Store refcount on RecoveryTarget

We should make sure we have incremented the store refcount
before we start the recovery on the recovyer target.

Closes #6844
[ENGINE] Mark store as corrupted before sending failed shard

We have to mark a shard as corrupted if necessary before the
shard failed event is fired ie. before we call the corresponding
listener in the engine. Otherwise the shard might be re-allocated
on the same node and just started up without being marked as corrupted.

Relates to #5924
[Transport] possible NPE during shutdown for requests using timeouts

Closes #6849
significant terms: infrastructure for changing easily the significance heuristic

This commit adds the infrastructure to allow pluging in different
measures for computing the significance of a term.
Significance measures can be provided externally by overriding

- SignificanceHeuristic
- SignificanceHeuristicBuilder
- SignificanceHeuristicParser

closes #6561
Analysis: Improve Hunspell error messages

The Hunspell service would throw a confusing error message if more than
one affix file was present.  This commit distinguishes between the two
error cases: where there are no affix files and when there are too many
affix files.

Also implements lazy dictionary loading, which was used in the tests
but not implemented.
Converted string settings to constants