Close autocomplete drop-down on tabKey

[xomaczar]

To reproduce:

1. In e-p current demo (v1.0.0-alpha.8), click on any autocomplete, then hit 'tab' key w/o selecting/highlighting any items
2. The autocomplete drop-down stays open

Fix:

• When tab is invoked, just delegate to e-p-s component, which closes the drop-down by default.

[miguelcobain]

👍

[xomaczar]

thx