Add a list source section for adding recursion to pipelines.
Add an XML walker source section for walking a tree of elements
Yield default page items in xmlwalker
Get everything from the item before passing it on lest something modify it
Use the same Pdb instance to preserve breakpoints and other debugger state
pep8 and pyflakes fixes
Restore breakpoint test output checking
Add coverage for reporting xmlwalker children
Process root xmlwalker item for default page as well
Tighten up expected xmlwalker test output
Expand on listsource docs: loops vs recursion, memory considerations
Skip already seen trees in xmlwalker
Match test output for easier debugging
Fix dropping of original xmlwalker item when skipping seen trees
Better testing output for debugging failures
Remove unused option
Document intentions of defaults
Better key ordering
Simpler xmlwalker child handling, use default page and type keys by default
Fix handling of optional xmlwalker parent key