Properly uncheck folders in selection dialog

- Properly check isAdded flag to check/uncheck folders from savedInstanceState.
- Rename isPresent -> isSelected for FolderRow for better consistency.
- Remove isSelected from ordering because we now add the originally selected
folders in a different section of the adapter so that they are always on top.
- Add section headers for the initially selected folders and the rest.

b/9174917

Change-Id: I0f063e9280312a1c2a9c76e604e6a9f799f72822
5 files changed