Add worldwide to nav & ensure selected is correct

Added intergration test to check to see if all controllers have an
active item in the navigation. I copied the style of test from the title
intergration test.

Also updated the documents drop down is selected when sub-types of
dropdown are visited.

https://www.pivotaltracker.com/story/show/46700063
Merge pull request #377 from alphagov/world-nav

Add worldwide to nav & ensure selected is correct

https://www.pivotaltracker.com/story/show/46700063