#1874: adds workspace import, adds basic error handling

package.json

src/components/App.js

src/components/ErrorDialog.js

src/components/WorkspaceImport.js

src/components/WorkspaceMenu.js

src/containers/App.js

src/containers/CompanionArea.js

src/containers/ErrorDialog.js

src/containers/ManifestListItem.js

src/containers/ThumbnailNavigation.js

src/containers/WorkspaceImport.js

src/containers/WorkspaceMenu.js

src/locales/de/translation.json

src/locales/en/translation.json

src/state/actions/action-types.js

src/state/actions/config.js

src/state/actions/errors.js

src/state/actions/index.js

src/state/actions/workspace.js

src/state/reducers/config.js