Generalized Block Attributes expansion option with the addition of:
+skip, -skip, +container, -container, +spans, -spans, +specials,
-specials options.
Allow macro expansion in Block Attributes.
- Expand macros inside Quote definitions.
- Macro Line syntax relaxed to be any line starting with a macro
  invocation (previously had to be exactly one invocation).
Documentation update: Added 'scoped CSS' tip.