Add module configuration.
Extracted common node implementations from 'substance-document' and 'substance-article'.
Add an index file for each node type.
Fix regression.
Add a 'richparagraph' Node type.

This can contain (annotated) text, inline graphics, and inline formulas.
Add css classes for heading levels.
Fix type specification of RichParagraph.
Paragraphs are now rich.
Add new node types 'formula' and 'table'.
Views for formula and table.
Fix.
Don't trigger immediate rendering for now.
Remove legacy code.
Integrated Figure node.
Merge branch 'extended_nodeset' of https://github.com/substance/nodes into extended_nodeset
Add FigureView.

Taken from lens-article.
Fix regression.
Add convenience factory for Table.
Expose label.
Add cover node.