Merge pull request #212 from liquancss/master

this update fix the problem that an exception raised when calling PyQuery("<textarea></textarea>").text()

pyquery/pyquery.py

@@ -1064,7 +1064,7 @@ def html(self, value=no_default, **kwargs):
             tag = self[0]
             children = tag.getchildren()
             if not children:
-                return tag.text
+                return tag.text or ''
             html = tag.text or ''
             if 'encoding' not in kwargs:
                 kwargs['encoding'] = str