Term Vectors: Support for artificial documents

This adds the ability to the Term Vector API to generate term vectors for
artifical documents, that is for documents not present in the index. Following
a similar syntax to the Percolator API, a new 'doc' parameter is used, instead
of '_id', that specifies the document of interest. The parameters '_index' and
'_type' determine the mapping and therefore analyzers to apply to each value
field.
Nope it does not.

"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."