fdsn: add tests for bulk waveform download
fdsn: work on bulk waveform requests
fix test with StringIO and check for "read" attribute even if input has
"__iter__" because of StringIO
fdsn: implement bulk requests using list of net/sta/loc/cha/t1/t2 lists
as input
docstring
Merge pull request #651 from obspy/fdsn_bulk

fdsn: bulk waveform requests