Host my own swagger editor

### New feature

- Use results of [blinkboxbooks/swaggerific-editor](https://github.com/blinkboxbooks/swaggerific-editor) for the editor.
- Currently does not support the saving of YAML files back to swaggerific; I need to work with the team to find out how to deal with saving specific files.

This slightly unusual arrangement means the swaggerific repo is not ensumbered by the size of the swagger-editor repo *and* I don't have to include the `grunt` toolchain in swaggerific.