update search ets backend for new interface (bz://795)
update search ets backend for new interface (bz://795)

Mostly:
 - all of the multi_* became primary ops,
   with the single-arg ops going away
 - range is no longer a pre-plan operation, but instead an
   execution-time process (so it operates the same as stream,
   but over a range instead of a specific IFT)

Passes tests/run_all.sh just as well as merge_index at this point

xuejianhai/riak_search,wwezhuimeng/riak_search,basho/riak_search,wwezhuimeng/riak_search,basho/riak_search,xuejianhai/riak_search