This adds the possibility to add block level attributes:
{#id2}
> line
When enabled to will generate (for HTML) an id="id2" in the openening
tag of the block quote:
<blockquote id="id2">
<p>line</p>
</blockquote>
Only one block level attribute is allowed, if multiple are given only
the last one seen is applied, the rest is silently ignored.
The attributes are stored in *Parser and copied to the node in addBlock.
It's up to the renderer to use the attributes, the html renderer
currently applies them to most block level elements.
Signed-off-by: Miek Gieben <miek@miek.nl>
Miek Gieben