GTFS test data from:

test1.zip - http://timetablepublisher.googlecode.com/files/GTFS%20Test%20Data.zip downloaded on Apr 14th, 2012
test2.zip - https://developers.google.com/transit/gtfs/examples/sample-feed.zip on Apr 14th, 2012
test3.zip - http://www.tulsatransit.org/gtfs/google_transit.zip, around Feb 2013
test4.zip - http://gtfs.s3.amazonaws.com/trimet_20150219_0157.zip on Feb 24, 2015

test1.zip doesn't pass validation, because of the directory structure.  It
has multiple trip_ids, assigned to different service_ids.  multigtfs will
import the feed, and (as of v0.4.0) will discard the duplicate trip IDs
with a warning.

test2.zip has some validation issues as well, with a mispelled column name
(drop_off_time vs drop_off_type) and inconsistant commas.  multigtfs will
import the feed, and (as of v0.4.0) will import the drop_off_type as an
unknown extra column.

test3.zip is a minimized version of an official feed.  It has one quirk - a
utf-8 encoded control character in the stop description of stop 5640.
The only validation error is that the last service date is in the past.
multigtfs will import and export the feed with no changes.

test4.zip is one route from the Portland Trimet archived feed.  This feed uses
the alternate method of specifying applicable dates, omitting ``calendar.txt``
and instead including each date in ``calendar_dates.txt``.  This feed fails in
v0.4.2 and earlier, but was fixed in v0.4.3.  It includes several extra columns
that cause feed validation errors.  It also includes tables such as
``stop_features.txt`` that are not in the GTFS spec, and are not imported.
