TABernacle: support auto-complete for items (Q...) and properties (P...) by name

[Waldir Pimenta]

Ideally this should work similarly to the Wikidata Query service, where you can start typing the name of an item or a property, press Ctrl+Space and a drop-down list will appear to auto-complete the Q or P number.

This is somewhat related to issue #67.

[Waldir Pimenta]

The feature has been implemented!