term vector request: new feature for retrieving the term vectors for a specific document

Term vectors consist of term frequency, term positions, start/end offsets and payloads.
Depending on if these four items were stored in the index, the TermVectorResponse returns
them if requested.

Apart from the classes needed for implementing the feature in package

src/main/java/org/elasticsearch/action/termvector/  and
src/test/java/org/elasticsearch/test/integration/termvectors/

and the registration of the fuctionallity in

src/main/java/org/elasticsearch/client/Client.java
src/main/java/org/elasticsearch/client/support/AbstractClient.java and
src/main/java/org/elasticsearch/client/transport/TransportClient.java

, this commit introduces the following 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.