Add more information and options in PluginManager
New option -l, --list displays list of existing plugins
New option -h, --help displays help
Deprecate options:
   -install is now -i, --install
   -remove is now -r, --remove
   -url is now -u, --url
Catch ArraysOutOfBoundException when no arg given to install, remove or url option
Add description on plugin name structure:
- elasticsearch/plugin/version for official elasticsearch plugins (download from download.elasticsearch.org)
- groupId/artifactId/version   for community plugins (download from maven central or oss sonatype)
- username/repository          for site plugins (download from github master)
Closes #3112.
Allow negative slops in SpanNearQueryParser

This is mainly due to the fact that SpanNearQuery allows some neat
tricks with negative slops to run zero-sloped near queries across
2 or more SpanTermQueries.

Closes #3079
Improve integration testing by reusing an abstracted cluster across tests

The new AbstractSharedClusterTest abstracts integration testing further to
reduce the overhead of writing tests that don't rely on explict control over
the cluster. For instance tests that run query, facets or that test highlighting
don't need to explictly start and stop nodes. Testing features like the ones
just mentioned are based on the assumption that the underlying cluster can
be arbitray. Based on this assumption this base class allows to:

 * randomize cluster and index settings if not explictly specified
 * transparently test transport & node clients
 * test features like search or highlighting on different cluster sizes
 * allow reuse of node insteance across tests
 * provide utility methods that act as upper or lower bounds that a test must pass with
   ie. if a test requries at least 3 nodes then it should also pass with 4 nodes
 * given a cluster has unmodified cluster settings (persistent and transient) the cluster
   should not differ to a fresh started cluster when reused across nodes.
 * within a test the client implementation and the clients associated node can be changed
   at any time and should return a valid result.

This patch also prepares some redundant tests like 'RelocationTests.java' for randomized
testing. Test like this are very long-running on some machines and run the same test with
different parameters like 'number of writers' or 'number of relocations' which can easily
be chosen with a random number and run only ones during development but multiple times
during CI builds.

All the improvements in this change reduce the test time by ~30%
term vector request
================================

Returns information and statistics on terms in the fields of a particular document as stored in the index.

        curl -XGET 'http://localhost:9200/twitter/tweet/1/_termvector?pretty=true'

Tree types of values can be requested: term information, term statistics and field statistics.
By default, all term information and field statistics are returned for all fields but no term statistics.

Optionally, you can specify the fields for which the information is retrieved either with a parameter in the url

	curl -XGET 'http://localhost:9200/twitter/tweet/1/_termvector?fields=text,...'

or adding by adding the requested fields in the request body (see example below).

Term information
-------------------------

- term frequency in the field (always returned)
- term positions ("positions" : true)
- start and end offsets ("offsets" : true)
- term payloads ("payloads" : true), as base64 encoded bytes

If the requested information wasn't stored in the index, it will be omitted without further warning.
See [mapping](http://www.elasticsearch.org/guide/reference/mapping/core-types/) on how to configure your index to store term vectors.

Term statistics
-------------------------

Setting "term_statistics" to "true" (default is "false") will return

- total term frequency (how often a term occurs in all documents)
- document frequency (the number of documents containing the current term)

By default these values are not returned since term statistics can have a serious performance impact.

Field statistics
-------------------------

Setting "field_statistics" to "false" (default is "true") will omit

- document count (how many documents contain this field)
- sum of document frequencies (the sum of document frequencies for all terms in this field)
- sum of total term frequencies (the sum of total term frequencies of each term in this field)

Behavior
-------------------------

The term and field statistics are not accurate. Deleted documents are not taken into account. The information is only retrieved for the shard the requested document resides in. The term and field statistics are therefore only useful as relative measures whereas the absolute numbers have no meaning in this context.

Example
-------------------------

First, we create an index that stores term vectors, payloads etc. :

    curl -s -XPUT 'http://localhost:9200/twitter/' -d '{
        "mappings": {
            "tweet": {
                "properties": {
                    "text": {
                                "type": "string",
                                "term_vector": "with_positions_offsets_payloads",
                                "store" : "yes",
                                "index_analyzer" : "fulltext_analyzer"
                         },
                     "fullname": {
                                "type": "string",
                                "term_vector": "with_positions_offsets_payloads",
                                "index_analyzer" : "fulltext_analyzer"
                         }
                 }
            }
        },
        "settings" : {
            "index" : {
                "number_of_shards" : 1,
                "number_of_replicas" : 0
            },
            "analysis": {
                    "analyzer": {
                        "fulltext_analyzer": {
                            "type": "custom",
                            "tokenizer": "whitespace",
                            "filter": [
                                "lowercase",
                                "type_as_payload"
                            ]
                        }
                    }
            }
         }
    }'

Second, we add some documents:

    curl -XPUT 'http://localhost:9200/twitter/tweet/1?pretty=true' -d '{
      "fullname" : "John Doe",
      "text" : "twitter test test test "

    }'

    curl -XPUT 'http://localhost:9200/twitter/tweet/2?pretty=true' -d '{
      "fullname" : "Jane Doe",
      "text" : "Another twitter test ..."

    }'

The following request returns all information and statistics for field "text" in document "1" (John Doe):

     curl -XGET 'http://localhost:9200/twitter/tweet/1/_termvector?pretty=true' -d '{
                    "fields" : ["text"],
                    "offsets" : true,
                    "payloads" : true,
                    "positions" : true,
                    "term_statistics" : true,
                    "field_statistics" : true
            }'
Equivalently, all parameters can be passed as URI parameters:
     curl -GET 'http://localhost:9200/twitter/tweet/1/_termvector?pretty=true&fields=text&offsets=true&payloads=true&positions=true&term_statistics=true&field_statistics=true'

Response:

     {
      "_index" : "twitter",
      "_type" : "tweet",
      "_id" : "1",
      "_version" : 1,
      "exists" : true,
      "term_vectors" : {
        "text" : {
          "field_statistics" : {
            "sum_doc_freq" : 6,
            "doc_count" : 2,
            "sum_ttf" : 8
          },
          "terms" : {
            "test" : {
              "doc_freq" : 2,
              "ttf" : 4,
              "term_freq" : 3,
              "pos" : [ 1, 2, 3 ],
              "start" : [ 8, 13, 18 ],
              "end" : [ 12, 17, 22 ],
              "payload" : [ "[64 32 39 79 5a 41 3d 3d]", "[64 32 39 79 5a 41 3d 3d]", "[64 32 39 79 5a 41 3d 3d]" ]
            },
            "twitter" : {
              "doc_freq" : 2,
              "ttf" : 2,
              "term_freq" : 1,
              "pos" : [ 0 ],
              "start" : [ 0 ],
              "end" : [ 7 ],
              "payload" : [ "[64 32 39 79 5a 41 3d 3d]" ]
            }
          }
        }
      }
    }

Further changes:
-------------------------

XContentBuilder
new method
public XContentBuilder field(XContentBuilderString name, int offset, int length, int... value)
to put an integer array.

IndicesAnalysisService
make token filter for saving payloads available in elasticsearch

AbstractFieldMapper/TypeParser
make term vector options string available and also fix the parsing of this string:
with_positions_payloads is actually allowed as can be seen in TermVectorsConsumerPerFields.

Closes #3114