1999-07-02  Michael Natterer  <mitschel@cs.tu-berlin.de>

	* app/[all tools]: the Tool structure is now allocated by a common
	constructor which sets default values and provides default tool
	action functions. To get rid of much code duplication there should
	be a object hierarchy of tools.

	* app/context_manager.c
	* app/tools.[ch]: create and destroy private contexts for the
	paint tools on startup and exit. They are not used yet.

	* app/interface.c
	* app/menus.c
	* app/tools.h: num_tools is now exported in tools.h

	* app/commands.c
	* app/gdisplay.c
	* app/menus.c: made "Toggle Selection" a toggleable menu item.