Change table padding and header colours

Closes #1130 

Before:

![local_government_elections____shineyoureye-2](https://f.cloud.github.com/assets/187630/1940138/53f66d22-7f71-11e3-9aa0-d5f959e87b6a.png)

After:

![table_test____shineyoureye-5](https://f.cloud.github.com/assets/187630/1940144/6a91f038-7f71-11e3-9faa-4a0f559302c6.png)

This change applies to all tables created in markdown for all countries as it is probably the desired behaviour.