fix: handle invalid html in github responses

stgithub.py

@@ -466,7 +466,14 @@ def user_daily_contrib_num(self, user, year):
         url = "/users/%s/contributions?from=%d-12-01&to=%d-12-31&full_graph=1" \
               % (user, year, year)
         year = str(year)
-        tree = ElementTree.fromstring(self._request(url).text)
+        start_token = '<svg'
+        stop_token = '/svg>'
+        response_text = self._request(url).text
+        # cut out first <svg> element,
+        # since HTML outside of it is sometimes malformed
+        response_text = start_token + response_text.split(
+            start_token, 1)[-1].split(stop_token, 1)[0] + stop_token
+        tree = ElementTree.fromstring(response_text)
 
         return {rect.attrib['data-date']: _int(rect.attrib.get('data-count'))
                 for rect in tree.iter('rect')
@@ -524,6 +531,11 @@ def full_user_activity_timeline(self, user, start=None, to=None):
         # type: (str, str, str) -> Generator[Tuple[str, Dict]]
         """ Get a list of public user contributions, by month by repository.
 
+        .. note: User timeline sometimes does not include all contributions.
+            E.g., this issue is not reflected in the reporter timeline:
+            https://github.com/GoogleCloudPlatform/webapp2/issues/104
+            Maybe, it
+
         Args:
             user (str): GitHub login of the user to get activity for.
             start (str): date to start with, e.g. '2017-01' or '2017-01-01'.