Added UNICODE_CHARACTER_CLASS support to Regex flags. This flag is only supported in Java7 and is ignored if set on a java 6 JVM

Closes #2895
Allow PolygonBuilder to create polygons with hole

Closes #2899
Added support for the `_cache` and` _cache_key` options to the `has_child` and `has_parent` filters.
Closes #2900
Better error messaging when postings_format can be resolved or when a custom postings_format type can't be instantiated.
Relates to #2893
only return primary if it is active in PlainOperationRounting

Closes #2896
Search Stats: Add current open searches
closes #2906
use more aggressive concurrency levels for CHM
- long running ones with high update rates
- also expose a *system* property of es.useConcurrentHashMapV8 to use the new non blocking Java8 CHM impl
If a value/field is a Calendar, it will be converted to a Date using getTime()
Closes #2911
# Response for Cluster Settings Update API

If cluster settings are update the REST API returns the accepted values. For
example, updating the `cluster.routing.allocation.disable_allocation` via
cluster settings:

```curl -XPUT http://localhost:9200/_cluster/settings -d '{
    "transient":{
        "cluster.routing.allocation.disable_allocation":"true"
    }
}'```

will respond:

```{
    "persistent":{},
    "transient":{
        "cluster.routing.allocation.disable_allocation":"true"
    }
}```

Closes #2907
make object caching optional
allow CacheRecycler to be cleared via the REST API
s/ES.RECYCLE/es.cache.recycle
remove size bound from cache recycler for performance reasons
Support empty string in FSTBytesAtomicFieldData
Apply minimum_should_match to inner clauses of multi_match query
When specifying minimum_should_match in a multi_match query it was being applied
to the outer bool query instead of to each of the inner field-specific bool queries.

Closes #2918
Added tests for multi_match with minimum_should_match
use Double/Float.compare for stable and correct float sort order
Added more test assertions
Remove per-doc ord collector callback infavor of an iterator
Cut over StringScriptDataComparator to use BytesRef instead of Strings

Closes #2920