In manage mode, touching launches a VIEW intent for the file. Also adds actions for sharing and deleting. Move roots and thumbnail caches into Application object, and flush cache when thumbnail size changes. Listen for package changes and broadcasts that should invalidate our roots cache. Pick default grid/list mode based on provider hint. Bug: 10329983, 10330210, 10378834, 10330069 Change-Id: I75afb1c58ab71bb9d55852b1059da7257a376248