Parse the Ordnance Survey Code-Point Open postcode data download, and generate latitudes and longitudes for each postcode.

The Ordnance Survey provides a fantastic download of all UK postcodes along with location and local authority information. However, it does not include latitude and longitude data, but uses it's own grid reference system. This script will parse the OS download and convert these to more conventional geographic references based on the WGS-84 coordinates system.

1. Download the Code-Point Open dataset https://www.ordnancesurvey.co.uk/opendatadownload/products.html
2. Unzip it to some directory.
3. Install Mapnik, including the Python bindings https://github.com/mapnik/mapnik/wiki/Mapnik-Installation
4. Pass the directory name from 2 to the post_code_data_generator() method.
5. Iterate over the resulting dictionaries and do what you want with the data.