scrapy/scrapy — pull request #393 by pablohoffman (2013-09-23 19:45:13+00:00)
Title: Make ITEM_PIPELINE setting a dict

This is for consistency with how spider and downloader middlewares are
defined. ITEM_PIPELINE_BASE was also added and both remain empty.

Backwards compatibility is kept (with a warning) with list-based
ITEM_PIPELINES.