Add support for importing file in one document per line format without an option needed.
Fix ending with an empty chunk per comments in #2764.
With a document per line format the EOF is the end of JSON.
Merge pull request #2764 from grandquista/grandquista/Add_document_per_line_import

Document per line format without an option needed.
Don't try to support old cluster versions in the directory_read_manager, when we don't do it anywhere else in the cluster code.
Removed version parameter to on_message()
fixing memory leaks when datum_t construction throws
changing datum_t::data_wrapper_t to be RAII
fixing build
Merge branch 'next' of github.com:rethinkdb/rethinkdb into next
Merge branch 'next' into daniel_geo