* tools/dbus-send.c: Don't exit with an error code if --help was
	passed.  Default to using the session bus instead of the system
	one.

	* tools/dbus-launch.c: Ditto.

	* tools/dbus-monitor.c: Ditto.

	* tools/dbus-send.1: Update with new arguments.

	* tools/dbus-launch.c: Emit code to export variables.  New
	arguments -s and -c to specify shell syntax, and a bit of code to
	autodetect syntax.  Also, allow specifying a program to run.

	* tools/dbus-launch.1: Update with new arguments.

	* tools/dbus-send.1: Ditto.

	* tools/dbus-monitor.1: Ditto.