Fakeapi code moved out of spec folder

@abersager
@maxfliri
Inject fakeapi as dependency and avoid conditional bootstrap

@abersager
@maxfliri
All fakeapi initialization in development.rb

@maxfliri
@abersager
Pass js config to layout as a hash of data attributes

@maxfliri
Nicer check for optional configuration proeprties

@maxfliri
Merge branch 'master' into fakeapi-refactoring
Update README with current stub date instructions

@maxfliri
Merge pull request #80 from alphagov/fakeapi-refactoring

Fakeapi refactoring