Added all_projects, all_tasks, all_notes, and all_items methods to TaskPaperDocument, returning a flat, depth-first (pre-order) array of all the appropriate types of item.
Added all_projects, all_tasks, all_notes, and all_items methods to TaskPaperDocument, returning a flat, depth-first (pre-order) array of all the appropriate types of item.

mattgemmell/TaskPaperRuby,mattgemmell/TaskPaperRuby