When links are not allowed, the email field does not exist and
autocomplete returns null. This causes Javascript errors.
The fix prevents entering the bogus block when links aren't allowed, as
it doesn't make sense to enter it in such cases anyway.
The parts of the remote share owner name is now split between user name,
domain name and root so they can be formatted / displayed differently.
The user name + domain name are displayed in the tooltip.
Since OC.Share didn't have any array containing the list of shares for
the current file, OC.Share.currentShares has been introduced to contain
the full share item structure instead of the reduced one
OC.Share.itemShares.
The event "sharesChanged" is now passing OC.Share.currentShares, which
itself includes the display name to be displayed for the recipients in
the action icon.
