fixes fetching/searching on mac os x. see d11wtq/oedipus#3

hi, first thanks for developing this gem, which i think is really great. unfortunately, on os x i encountered the same problem as described in #3.

i first tried various sphinx versions. with strange results. using sphinx 2.0.3 & 2.0.4 whenever i tried to run the integration tests, my macbook crashed and rebooted. using 2.0.6 i have the #3 problems.

that's why i picked up your guess that this could be related to multi queries and converted them to single queries executed in serial. i guess this might slow down the implementation a bit (?), but at least the basic functionality now seems to be working. i had to pend some tests though.

cheers,
johannes.