Fixed issue where facets could not be changed when you are logged in

Issue 313: add support for paginated properties on dspace objects

Issue 311: No files item page bugfix

#293 Added link with the query quoted for search results if empty

If there is an error 400 or a search returns an empty result this commit will show a link with the query quoted. 
Also improved testing of search results component as the component has changed.

Hide metadata labels without value

Initial German Translation 

Issue #295 Dutch translation

Czech translation

Fix for authentication

Update version of Bootstrap per CVE-2018-14041

Issues 252,253: Browse by title and browse by metadata (author)

Conflicts:
	src/app/core/shared/operators.ts

Resolvers for item, collection and community home page