Make grammar look Python-esque
Support multiple filters per node type.
Change filtering model again to allow more complex filters.
Revert "Change filtering model again to allow more complex filters."

This reverts commit a49c9f6db8954df290560541a2f997798f401595.
Revert "Revert "Change filtering model again to allow more complex filters.""

This reverts commit 0f86637a6c7f6d10ffc23b429a62b1bfa0bdac7b.
More filters needed to support mediawiki list parsing.