toolbar and feature parity

re toolbar and feature parity:

List of Markdown not yet replicated in toolbar
- Heading 2-6 (heading 1 shall not be used so better not to encourage it - Heading 5 and 6 will probably not be used)
- Blockquote
- List, both ordered and unordered
- code, both block (<pre><code>) and inline (<code>)
- horizontal rule (I for one use it from time to time but if only HTML input is possible, I won't die, although it would break the principle of feature parity)
- Anchor links (probably tricker to handle UX-wise, low-priority)