This is the third part of what used to be as66c.  The patch makes several
changes in the routines that handle unbinding and selecting altsettings
and configurations.

	Upon unbinding a driver, don't nuke all the URBs for the device
	-- only kill the ones on the driver's interface.  Afterwards,
	reinitialize the interface by selecting altsetting 0 (the
	default).

	When changing an altsetting, if the interface has only one
	altsetting it is allowed to STALL the request.  Attempt to carry
	out the equivalent initialization by clearing the HALT feature
	on each of the interface's endpoints.

	When changing configurations, mark each interface as being in
	altsetting 0.

	In general, use the new disable/enable routines instead of doing
	everything by hand.