fixed a rather large memory leak

sleekxmpp/stanza/error.py

@@ -22,7 +22,7 @@ class Error(ElementBase):
 			self['type'] = 'cancel'
 			self['condition'] = 'feature-not-implemented'
 		if self.parent is not None:
-			self.parent['type'] = 'error'
+			self.parent()['type'] = 'error'
 	
 	def getCondition(self):
 		for child in self.xml.getchildren():

sleekxmpp/stanza/htmlim.py

@@ -31,4 +31,5 @@ class HTMLIM(ElementBase):
 		return html
 	
 	def delHtml(self):
-		return self.__del__()
+		if self.parent is not None:
+			self.parent().xml.remove(self.xml)

sleekxmpp/stanza/nick.py

@@ -22,4 +22,5 @@ class Nick(ElementBase):
 		return self.xml.text
 	
 	def delNick(self):
-		return self.__del__()
+		if self.parent is not None:
+			self.parent().xml.remove(self.xml)