Completed navigation for product-related models.

The navigation bar in the admin zone is complete for the products tab.
Completed coarse navigation in Admin zone

Most of the pages in the admin zone are now acessible through the tabs.
added admin_X role support
Merge branch 'hotfix/multi_admin_roles'
Merge branch 'hotfix/multi_admin_roles' into develop
Merge branch 'develop' of github.com:Plazr/plazr_store into develop
Merge branch 'develop'