Allow setting individual breakers to "noop" breakers

This adds a NoopCircuitBreaker, and then adds the settings
`indices.breaker.fielddata.type` and `indices.breaker.request.type`,
which can be set to "noop" in order to use a breaker that will never
break, and incurs no overhead during computation.

This also refactors the tests for the CircuitBreakerService to use
@Before and @After functions as well as adding settings in
ElasticsearchIntegrationTest to occasionally use NOOP breakers for all
tests.
[TESTS] Add a benchmark for circuit breaker overhead
Update plugins.asciidoc

Added Vietnamese Analyser to plugins page

Closes #6647
Eclipse: do not use star imports and reorganize imports on save.

Close #7587
Mappings: Store _timestamp by default.

Storing `_timestamp` by default means that under the default configuration, you
would have all the information you need in order to reindex into a different
index.

Close #8139
Search: Remove partial fields.

Partial fields have been deprecated since 1.0.0Beta1 in favor of _source
filtering. They will be removed in 2.0.
Test: RelocationTests.testMoveShardsWhileRelocation should wait on nodes to start before asking for a client

The client call may create another node if none of the previous nodes are published. That node throws the test off.
Raise maximum index name length to 255 bytes

Fixes #8079
Add time_zone setting for query_string

Query String query now supports a new `time_zone` option based on JODA time zones.
When using a range on date field, the time zone is applied.

```json
{
"query": {
  "query_string": {
    "text": "date:[2012 TO 2014]",
    "timezone": "Europe/Paris"
  }
 }
}
```

Closes #7880.
Parent/child: Reduce memory usage in top children query.

Closes #8165
Closes #8160
Tests: Adding additional debug info to upgrade test.
Boostrap: Log startup exception to console if needed and to file as error

Closes #6581
Change IndexPrimaryShardNotAllocatedException from 409 (RestStatus.CONFLICT) to 500 (RestStatus.INTERNAL_SERVER_ERROR)

Closes #7632, Closes #7987
Docs: Update minimum-should-match.asciidoc

Add %-sign to examle in the last section

Closes #8157
Docs: Update filtered-query.asciidoc

Fix mistyping

Closes #8167
Docs: Provide example of deleting a repository

Example of deleting a repository with explanation that snapshots themselves are left untouched.

Closes #8172
Tests: Fix SearchFieldsTests after changes to TimestampFieldMapper.
Docs: missing quote

fix missing quote

Closes #8176
Tests: Control reallocation in upgrade test to stop rebalancing causing upgrade requests to be lost.
Use groovy-x.y.z-indy jar for better scripting performance

Using the Groovy jar with the indy (short for `invokedynamic`) classifier enables usage of the `invokedynamic` instruction available in Java 7+. Due to buggy JVMs, it should only be used with Java 7u60 or later.