This reverts commit 5487769838570ba5f1b35529689321e1842bae31.
Come back to a more consistant UI:
  - single click for selection. CTRL modifier for multi-selection
  - double click for action
  - removed item's checkbox
  - get rid of the selection mode
  - no hover on items

Change-Id: I82863c77ed6a45410242a244545505a5b898ba56