Allow International Development Funds to be viewed

 * Add InternationalDevelopmentFund presenter
 * Add cucumber spec mirroring CMA cases.
 * Fix CMA case cucumber spec (was looking for nil)

Development/Test only:
 * Add launchy gem to allow save_and_open_page in test suite in future.
Merge pull request #34 from alphagov/view-international-development-fund

Allow International Development Funds to be viewed