Issue #611: Wrong created_at timestamp in trends/woeid.json API response

Response to https://api.twitter.com/1/trends/{woeid}.json API endpoint has 'created_at' set to unix epoch.

"https://api.twitter.com/1/trends/1.json" returns

[
{
"created_at": "1970-01-01T00:00:00Z",
"trends": [ … ],
"locations": [
{
"name": "Worldwide",
"woeid": 1
}
],
"as_of": "2012-10-18T22:04:22Z"
}
]