fix(media): fix media part to work with new backend

- Fix media listing and items preview
- Update tests
fix(media): enable pagination and filter by provider
Move sdShadow directive in a new superdesk/ui submodule

close #268
fix(users): fixed field names to reflect changes in server.
feature(settings): re-enable settings module

SD-156
feature(ingest): re-enable ingest module

SD-156
docs(contributing): add contributing info
fix(ingest): disable conflicting directives

SD-156
Update menu.html

Changed "Beta" to "Feature preview"

close #278
Update beta elements

- add media module to stable (but keep baskets in beta)
- move user profile additional tabs to beta
fix(beta): change label from beta to feature preview
fix(ingest): change media label to ingest
test(core): Added test for rejecting success response with issues.
fix(users): fixed sd-user-unique directive to use new api.