Patch on float field render to add:
  * replacement of spaces by unbreakable spaces if the content is float-like,
  * support of extra CSS class when render as pure text.


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@4115 20353a03-c40f-0410-a6d1-a30d3c3de9de