&nbsp is appeared in EPUB docs

[tk0miya]

Problem

•   entity is appeared in EPUB docs. It is not allowed in EPUB (XHTML5).

Procedure to reproduce the problem

.. list-table::
   :header-rows: 1
   - * one
     * two
     * three
   - * un
     * 
     * trois

Error logs / results

The generated EPUB file contains   entity

<tbody valign="top">
<tr class="row-even"><td>un</td>
<td>&nbsp;</td>
<td>trois</td>
</tr>
</tbody>

Expected results

It should be represented as SPACE character (0x20) or  .

[tk0miya]

Note: docutils.writers.html4css1.Writer generates   entity

• on encode() method (for 0xA0; non breaking space)
• on visit_entry() method if the table cell is empty

[shibukawa]

.. py:function:: test() -> string

makes →

[shibukawa]

Field-list that has more than limit of field name count characters (default 14)

:abcdefghijklmnopqrstuvwxyz: fieldlist

makes  

[shibukawa]

Option-list that has more than limit of option name count characters (default 14)

-a                 all
-b long_long_file  use file

makes