Eclipse: organize imports on save.

It can happen that Eclipse fails at correctly adding a new import entry to an
existing list of imports since we don't use its default rules. This commit
forces Eclipse to organize imports on save.
Optimize `has_child` query & filter execution with two short circuit mechanisms:
* If all parent ids have been emitted as hit, abort the query / filter execution.
* If the a relative small number of parent ids have been collected in the first phase then limit the number of second phase parent id lookups by putting a short circuit filter before parent document evaluation or omit the it in the case of the filter. This is contrable via the `short_circuit_cutoff` option which is exposed in the `has_child` query & filter.

All parent / child queries and filters (expect `top_children` query) abort execution if no parent ids have been collected in the first phase.

Closes #3190
Make field data able to support more than 2B ordinals per segment.

Although segments are limited to 2B documents, there is not limit on the number
of unique values that a segment may store. This commit replaces 'int' with
'long' every time a number is used to represent an ordinal and modifies the
data-structures used to store ordinals so that they can actually support more
than 2B ordinals per segment.

This commit also improves memory usage of the multi-ordinals data-structures
and the transient memory usage which is required to build them (OrdinalsBuilder)
by using Lucene's PackedInts data-structures. In the end, loading the ordinals
mapping from disk may be a little slower, field-data-based features such as
faceting may be slightly slower or faster depending on whether being nicer to
the CPU caches balances the overhead of the additional abstraction or not, and
memory usage should be better in all cases, especially when the size of the
ordinals mapping is not negligible compared to the size of the values (numeric
data for example).

Close #3189
Work around the fact that AssertionError(String message, Throwable cause) is a Java 1.7-only API.
top level filter not resulting in an actual filter is ignored
when parsing a filter, we use null to indicate that this filter should not match anything, the top level filter doesn't take it into account
fixes #3356
bound the capacity of stream handles
if the capacity of stream handles increase beyond a reasonable size, reset it, so other requests won't incur the cost of clearing it
this is a patch in 0.90, in master we can fix it in a better way (introduce a shared string concept and use it only where it makes sense)
relates to #3322
Limits are not consumed using Systemd (ulimit -n / ulimit -l)

See http://www.freedesktop.org/software/systemd/man/systemd.exec.html
* LimitNOFILE
* LimitMEMLOCK
pattern replace with empty "" setting fails
we should default the replacement to "", since in the settings, if its set to "", we remove the setting
Be consistent with the default value of `acceptable_overhead_ratio`.
Zen Discovery Cluster Events to have Priority.URGENT
Master node cluster state events resulting in zen discovery (node gets added, removed, for example) should be processed with priority URGENT as its always better to process them as fast as possible, and not let other events get in the way.
closes #3361
reroute post shard started should have HIGH prio as well
add ability to associate a timeout with a priority executor
enhancement that can be used later to timeout tasks that are pending, also added the ability to get the pending task list from the executor
Transport: Add a dedicated ping channel
Today, we have a low/med/high channel groups in our transport layer. High is used to publish cluster state and send ping requests. Sometimes, the overhead of publishing large cluster states can interfere with ping requests.

Introduce a new, dedicated ping channel (with size 1) to have a channel that only handles ping requests.
closes #3362
catch failures and notify the listener in aliases action handling
Added alias action validation

Moved alias action validation to IndicesAliasesRequest, so that Java api and RestIndexPutAliasAction can benefit from it too.
Added check in MetaDataIndexAliasesService too.

Closes #3363
Cluster State Update APIs (master node) to respect master_timeout better
Currently, the master node might be processing too many cluster state events, and then be blocked on waiting for its respective even to be processed. We can use the new cluster state update timeout support to use the master_timeout value and respect it.

closes #3365
Cluster State Update APIs (master node) to respect master_timeout better
Currently, the master node might be processing too many cluster state events, and then be blocked on waiting for its respective even to be processed. We can use the new cluster state update timeout support to use the master_timeout value and respect it.

closes #3365
Cluster State Update APIs (master node) to respect master_timeout better
also respect the timeout when trying to obtain the md lock
relates #3365
should be 500...
Add FastVectorHighlighter support for more complex queries.

FastVectorHighlighter fails at highlighting some complex queries such as
multi phrase queries which have two terms at the same position. This can be
easily triggered by running a `match_phrase` query with an analyzer which
outputs synonyms such as SynonymFilter or WordDelimiterFilter.

Close #3357