Allow a rootless navigation structure

[Facundo Batista]

Currently, the 7digital scope is returning this structure for the categories/departments/navigation:

{'canned_query': 'scope://com.canonical.scopes.sevendigital',
 'label': 'All categories',
 'subdepartments': [{'canned_query': 'scope://com.canonical.scopes.sevendigital?dep=newreleases',
                     'has_subdepartments': False,
                     'label': 'New releases'},
                    {'canned_query': 'scope://com.canonical.scopes.sevendigital?dep=topalbums',
                     'has_subdepartments': False,
                     'label': 'Top albums'},
                    {'canned_query': 'scope://com.canonical.scopes.sevendigital?dep=toptracks',
                     'has_subdepartments': False,
                     'label': 'Top tracks'},
                    {'canned_query': 'scope://com.canonical.scopes.sevendigital?dep=genres',
                     'has_subdepartments': True,
                     'label': 'Genres'}]}

However, Design requested for this structure to be rootless, to don't have a "All categories" root in the beginning. Currently, if the server returns the needed structure, it doesn't work ok.

Talking with Pawel and Albert they agreed works needs to be done in this project for this to be possible.

[Facundo Batista (facundo)]

Related bugs in other projects:

https://bugs.launchpad.net/unity-scopes-api/+bug/1364341
https://bugs.launchpad.net/unity8/+bug/1364342