0.9.15.45:

0.9.15.45:
	Make ENSURE-CLASS and ENSURE-GENERIC-FUNCTION do what AMOP says
	regarding the :METACLASS and :GENERIC-FUNCTION-CLASS default
	arguments.  I don't like it, but that's what it says, and as
	Bruno points out on sbcl-devel, no default is right in all
	circumstances.
	... we didn't call ENSURE-CLASS ourselves except as part of
		DEFCLASS' expansion; we did call
		ENSURE-GENERIC-FUNCTION, so arrange to call it only
		when necessary and only with the right
		:generic-function-class argument.
	... while we're at it, fix a bug in ENSURE-CLASS, which got
		the metaclass wrong if the argument was provided
		more than once.
	... document one or two more small MOP deviations in the
		manual.