batch of patches from twaugh:

batch of patches from twaugh:
* This patch (based on one from Jirka Kosek) adds support for
  block-level elements inside <para>s---<screen>s for example, or lists.
* This patch replaces entities (like '&#x8212;') with sensible
  characters or groups of characters.
* This patch adds support for sbr.
* This patch normalizes spaces in varlistentry terms.
* This patch normalizes spaces in terminal varlistentry terms.
* This patch allows variable lists to be nested (once).
* This patch prevents variable list item paragraphs from merging into
  one another.
* This patch improves the rendering of itemized lists, and adds support
  for ordered lists and procedures.
* This patch makes some small adjustments to group/arg: don't put extra
  spaces in where they aren't needed, and normalize the space of $arg.
* This patch makes adjustments to cmdsynopsis elements.  In particular,
  they can now be wrapped if no <sbr/> is provided.
* This patch adds funcsynopsis//* support.  Again, wrapping is done
  automatically.