we now use a multiphrase query in all cases
internally its optimized to be the same as regular phrase query
anyway, and we simplly map all the tokens in the stream into
a multi-phrase query with the appropriate structure
This is a change in search result behavior in that location
information is no longer provided by default with search results.
Although this looks like a wide-ranging change, it's mostly a
mechanical replacement of the explain bool flag with a new
search.SearcherOptions struct, which holds both the Explain bool flag
and the IncludeTermVectors bool flag.
