fix cdmitests for new create_dirlist_gen()
fix most cdmi tests

add an re to cdmi.py for parsing the arguments
fix irodsstorage to use the correct stream generator

it needs its own, because the read() function is different
from the local read()
add output documentation to irods_read_stream_gen
remove unused stat elements from localstorage

those were only valid for irods-stored files
remove unused import from urlparse
add mockstorage.py

this is used for mock tests in unittests.py.
having to mock generator functions makes mocking the
storage class more difficult, so having a 'real' class
with which to mock makes it a bit simpler.