0.7.13.pcl-class.1

0.7.13.pcl-class.1
	Turn SB-PCL::CLASS into CL:CLASS
	... and to do that, turn CL:CLASS into SB-KERNEL:CLASSOID

Well, there's a little more to it than that.  This commit causes no
regressions against our own test suite (once the necessary
s/SB-PCL:FIND-CLASS/FIND-CLASS/ changes have been made) but, along with
several new passes in the gcl suite, causes one new failure to do with
condition classes.

There have been some code deletions, too, as some methods that were
necessary to paper over the cracks between the two different CLASSes are
now no longer necessary, as the CLASSOID structure is now viewed as
internal.  The major code addition is probably
SB-PCL::SET-CLASS-TYPE-TRANSLATOR, which communicates the necessary
information to the type engine (with extra hair to get BUILT-IN-CLASSES
right).

This branch is expected to last during the freeze period, and land
shortly after 0.7.14 is released.