Setting the right timestamp format.

So the conversion can work instead of returning the epoch start.
This fixes issue #5.
http://dev.croydon.randomness.org.uk/wiki.cgi?id=Sara%27s_Diner%2C_65_Church_Street;format=json to see it working.
Merge pull request #41 from OpenGuides/fix_json_date

Setting the right timestamp format.

merging since the travis ci run probably had github issuses.