fix(urls): make it work with server not returning server name

in order to fix deployment we had to drop server name from returned
urls. this makes client work with such urls.
fix(core): Response status can be overridden by eve-specific error response.

SD-296
fix(users): Fixed how server errors are represented.

SD-296
fix(urls): make it work with server url prefix

on resources endpoint / urls are returned absolute not relative
to server root url. now we parse server url setting and use only
protocol and host part when combined with returned href.
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