Updated issues with MySQL

I was having two issues installing this library.

The first is that MySQL does not allow 0 as a primary key, which is an issue for multiple countries in the `initial_data.json` file.  I've updated the fixture data to set these values to 900-905.  This actually is an issue for all databases, since it means only the last of those 6 countries would be imported.

The second issue was with encoding.  I know a lot of developers struggle with this sort of thing, and making the docs as easy as possible would probably be greatly appreciated by most.  I'm not sure about Markdown's format, but I believe I've updated it properly.

Thanks for the great library.