Fix HtmlParserLinkExtractor and tests after #485 merge
Merge pull request #575 from redapple/docs-tutorialindent

Docs: 4-space indent for final spider example
Merge pull request #574 from redapple/htmllx-tests

Fix HtmlParserLinkExtractor and tests after #485 merge
cleanup toplevel namespace
Add basic top-level shortcuts
move loaders to scrapy.loader