fix contributters list format
minor updates to 0.18 release notes
fix XmlItemExporter in Python 2.7.4 and 2.7.5
fix retry middleware which didn't retry certain connection errors after the upgrade to http1 client, closes GH-373
added quantal & raring to support ubuntu releases
Fixed so it refers to the correct folder
Merge pull request #375 from peterarenot/patch-1

Changed name of directory to save file to
limit travis-ci build matrix
New HTTP client wraps connection losts in ResponseFailed exception. fix #373
do no include ResponseFailed if http11 handler is not enabled
Treat responses without content-length or Transfer-Encoding as good responses

There is not a way to determine if responses without Content-Length or Transfer-Encoding are complete, this change treat them as good responses but flags them as "partial".
This is backout change only for this functionality of 3c64a989
test PotentiaDataLoss errors on unbound responses
py26 can not format zero length fields {}
fix crawling tests under twisted pre 11.0.0
remove extra import added by cherry picked changes
bumped version to 0.18.1
Add 0,18.1 release notes
fix a possible error in contracts post hook
command with multiple crawlers, fix check command
disable logging for scrapy check