cleanup tests
Add integration test for PluginManager

We want to make sure that Plugin Manager still downloading plugins from internet.
New tests requires internet access (`@Network` annotation has been added).

By default, tests annotated with `@Network` are not launched.

If you need to run these tests, use `-Dtests.network=true` option.

Closes #3894.
Support date math for `origin` decay function parsing

The parser used the method that was supposed to be used for parsing on
the indexing side that never supported date math.

Closes #3892
Fix toXContent of GeoShapeQueryBuilder

A missing endObject() resulted in serialization errors.

Closes #3878
remove irrelevant comment now that we pass the reuse strategy
Set queue sizes by default on bulk/index thread pools
Now that we properly fixed the ability to set the queue size on the index / bulk thread pool, we should actually set them to a somehow reasonable value to protect from users potentially overflowing our system.

I suggest defaults to be 50 for bulk, and 200 for indexing.

Also, set the thread pool for get, which we should set (in a similar value to a "read" queue size we have today).
closes #3888
Set queue sizes by default on bulk/index thread pools
Now that we properly fixed the ability to set the queue size on the index / bulk thread pool, we should actually set them to a somehow reasonable value to protect from users potentially overflowing our system.

I suggest defaults to be 50 for bulk, and 200 for indexing.

Also, set the thread pool for get, which we should set (in a similar value to a "read" queue size we have today).
closes #3888
Query String: Support multiple fields regexp queries
The query string query should apply regexp queries to execute on multiple fields as all the other queries.
closes #3901
test variations of multi field query string queries
[DOCS] Render common options on the same page
[DOCS] Reorganised common API conventions
[DOCS] Fixed a bad merge
Subclass ElasticSearchTestCase across the board

All tests in the test package should subclass ESTestCase to benefit from
random time-zones and locale etc.
s/ElasticSearch/Elasticsearch in src/test
Use smart client in busy waiting loop

This test fails since we use random transport clients. Let's see
if it stabelizes with a smart client in the loop and debug further
if it helps.
Added missing builder.endObject calls
Retry blocking if async indexing is rejected due to queue size

Some tests use AbstractIntegrationTest#indexRandom which sometimes uses async
indexing. This can easily run into queue size based rejections on a slow
box. In that case we should retry blocked indexing.
Randomly use Bulk in AbstractIntegrationTest#indexRandom
Segments API: Support merge id on segments (groups segments being merged)
Return a merge_id element in each segment of the segments API, allowing to group segments that are being merged as part of a single merge and indicate which ones are being merged now.
closes #3904
fix naming in function_score

    - "boost" should be "boost_factor"
    - rename "mult" to "multiply"

Because "mult" was introduced in 0.94, we keep both names and remove "mult"
completly from 1.0 on.

closes #3872 for 0.90