Make enforce_type an optional flag, to avoid conflicts

common/lib/xmodule/xmodule/fields.py

@@ -68,7 +68,10 @@ class Date(Field):
         """
         if value is None:
             return None
-        if isinstance(value, datetime.datetime):
+        if isinstance(value, time.struct_time):
+            # struct_times are always utc
+            return time.strftime('%Y-%m-%dT%H:%M:%SZ', value)
+        elif isinstance(value, datetime.datetime):
             if value.tzinfo is None or value.utcoffset().total_seconds() == 0:
                 # isoformat adds +00:00 rather than Z
                 return value.strftime('%Y-%m-%dT%H:%M:%SZ')

requirements/edx/github.txt

@@ -17,7 +17,7 @@
 -e git+https://github.com/appliedsec/pygeoip.git@95e69341cebf5a6a9fbf7c4f5439d458898bdc3b#egg=pygeoip
 
 # Our libraries:
--e git+https://github.com/FiloSottile/XBlock.git@a9158e9887217abe27e451d1ff82c0d9f98c0bd6#egg=XBlock  # TODO: put here the edx/XBlock#200 merge commit
+-e git+https://github.com/FiloSottile/XBlock.git@ee9aaa5e1cc267de62b0e9cb638461a55e630af9#egg=XBlock  # TODO: put here the edx/XBlock#200 merge commit
 -e git+https://github.com/edx/codejail.git@71f5c5616e2a73ae8cecd1ff2362774a773d3665#egg=codejail
 -e git+https://github.com/edx/diff-cover.git@v0.5.0#egg=diff_cover
 -e git+https://github.com/edx/js-test-tool.git@v0.1.5#egg=js_test_tool