D20838: Allow to drop one file or one folder on KDirOperator

[Nathaniel Graham]

ngraham added a task: T8552: Polish Open/Save dialogs.

REPOSITORY
  R241 KIO

REVISION DETAIL
  https://phabricator.kde.org/D20838

To: meven, ngraham
Cc: apol, kde-frameworks-devel, michaelh, ngraham, bruns