[docs] Advise everyone to use datetime.utcnow()

NOTES.md

@@ -29,7 +29,7 @@ We only create one datastream at a time.
 Datapoints
 ----------
 
-    >>> now = datetime.now()
+    >>> now = datetime.utcnow()
     >>> datapoints = datastream.datapoints.create([
     ...     {'at': now - timedelta(seconds=1), 'value': 42},
     ...     {'at': now, 'value': 43},
@@ -44,15 +44,15 @@ Historical Queries
 
 Fetching history of a datastream:
 
-    >>> datapoints = datastream.datapoints.history(end=datetime.now(), duration=1800)
+    >>> datapoints = datastream.datapoints.history(end=datetime.utcnow(), duration=1800)
 
 Retrieving a datastream with historical datapoints:
 
-    >>> datastream = feed.datastreams.get("energy", end=datetime.now(), duration="30minutes")
+    >>> datastream = feed.datastreams.get("energy", end=datetime.utcnow(), duration="30minutes")
     >>> datapoints = list(datastream.datapoints)
 
 Retrieving a feed and its datastreams with historical datapoints:
 
-    >>> feed = client.feeds.get(feed.id, end=datetime.now(), duration=3600, datastreams=[...])
+    >>> feed = client.feeds.get(feed.id, end=datetime.utcnow(), duration=3600, datastreams=[...])
     >>> print list(feed.datastreams[0].datapoints)
     [Datapoint(...), Datapoint(...), ...]

docs/index.rst

@@ -28,7 +28,7 @@ Example:
 
     >>> # Updating a feed
     >>> import datetime
-    >>> now = datetime.datetime.now()
+    >>> now = datetime.datetime.utcnow()
     >>> feed.datastreams = [
     ...     xively.Datastream(id='sensor1', current_value=37.2, at=now),
     ...     xively.Datastream(id='sensor2', current_value='normal', at=now),
@@ -39,9 +39,9 @@ Example:
     >>> # Uploading new points
     >>> import random
     >>> randompoints = [
-    ...     xively.Datapoint(datetime.datetime.now(), random.random()),
-    ...     xively.Datapoint(datetime.datetime.now(), random.random()),
-    ...     xively.Datapoint(datetime.datetime.now(), random.random()),
+    ...     xively.Datapoint(datetime.datetime.utcnow(), random.random()),
+    ...     xively.Datapoint(datetime.datetime.utcnow(), random.random()),
+    ...     xively.Datapoint(datetime.datetime.utcnow(), random.random()),
     ... ]
     >>> stream.datapoints = randompoints
     >>> stream.update(fields='datapoints')