Parsing of XML nodes without children types

[wisotzky]

I would like to have the ability in jxmlease to control how XML nodes w/o children are rendered. At the moment, this is done as empty string:

>>> x2 = jxmlease.parse("<a/>")
>>> x2
XMLDictNode(xml_attrs=OrderedDict(), value=OrderedDict([(u'a', XMLCDATANode(xml_attrs=OrderedDict(), value=u''))]))
>>> x2.prettyprint()
{u'a': u''}

So actually it means, that even has no children nodes, it is associated with an empty string. From an implementation point of view, I would like have the possibility to control how this is rendered. Technically it could be an empty list, empty dict or NoneType as well. Preferred implementation from my point of view would actually be the NoneType:

>>> x2 = jxmlease.parse("<a/>")
>>> x2.prettyprint()
{u'a': None}