Add album name label.
Update title for album name.
Refactoring for undo target.

The final goal is move undoable target inside command so that slid pop can be undoable.
But the goal seems too far for me, so I just check-in this transit stage.
Refactoring2. Make UndoCommand interface.
Refactoring. Move slide related code to WhiteBoardCanvas.
Implement undo for slide.
Update pop slide enable-disable status.
update pop-slide state when onRestart.

When go to SlideListActivity and change slides, WhiteBoardCastActivity should update floating overlay.
Remove non adequate message of SlideListActivity.
Rename title SlideListActivity->Manage Slides.
Avoid crash when edit slide list after adding undo list.
Disable slides menu during recording.
Fix wrongly stored previous activity slides.
Special handling for empty slide sequence. Go to image pick directly.
Implement delete all. Make long running task progressDialog.