Move the button to create permanode into toolbar.

Also:
* Make the entire BlobItemController a drop target for new files,
  except for when over a set, then the set is the target.
* Minor visual refinements to highlight states during dragging.
* Fix bugs/flicker in dragdrop code.
* Fix bug where there is an empty button in toolbar before the first
  item is selected.

Change-Id: I3c40a476395c885477e1316e6ff168399640e347
Add diskPack as a high level local storage destination, and storage-filesystem based sync queue

Change-Id: I9ec0583b160f89952cdad851e66c7fabf22b7bb4