* src/file-manager/fm-directory-view.c,
	src/file-manager/fm-directory-view.h
	(fm_directory_view_popup_item_context_menu,
	fm_directory_view_popup_background_context_menu): New functions
	for subclasses to call, to implement right-click menus. Most of
	the guts are here now. Machinery to merge view-specific items with
	generic ones will be added here.
	* src/file-manager/fm-directory-view-icons.c,
	src/file-manager/fm-directory-view-list.c: Use the new interface
	for right-click stuff.