BUG: Fix treasury loading.

Make adjustments for using Python built-in ElementTree instead of lxml
based lxml.

lxml was edited out during pulling in of memory friendly loading of
treasury curves, however some of the use of ETree was lxml specific.

Mea culpa.

zipline/data/treasuries.py

@@ -12,7 +12,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
+import re
 
 import requests
 
@@ -84,6 +84,11 @@ class iter_to_stream(object):
         return result
 
 
+def get_localname(element):
+    qtag = ET.QName(element.tag).text
+    return re.match("(\{.*\})(.*)", qtag).group(2)
+
+
 def get_treasury_source():
     url = """\
 http://data.treasury.gov/feed.svc/DailyTreasuryYieldCurveRateData\
@@ -106,11 +111,11 @@ http://data.treasury.gov/feed.svc/DailyTreasuryYieldCurveRateData\
 
     for event, element in elements:
         if event == 'end':
-            tag = ET.QName(element.tag).localname
+            tag = get_localname(element)
             if tag == "entry":
                 properties = element.find(properties_xpath[0])
-                datum = {ET.QName(node.tag).localname: node.text
-                         for node in properties.iterchildren()
+                datum = {get_localname(node): node.text
+                         for node in properties.getchildren()
                          if ET.iselement(node)}
                 # clear the element after we've dealt with it:
                 element.clear()