fixed issue with hostwindowservice, search filter bug, changed sidebar toggle text to pin, fixed mobile view of header

Conflicts:
	webpack.config.js

Angular6 upgrade

Hide the wrapper component when there is no text content

Conflicts:
	src/app/app.module.ts
	src/app/header/header.component.ts
	src/app/navbar/navbar.effects.ts

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

Conflicts:
	src/app/core/cache/builders/remote-data-build.service.ts
	src/app/core/metadata/metadata.service.ts
	src/app/core/shared/item.model.ts
	src/app/shared/loading/loading.component.ts
	yarn.lock

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