Make a new instance of CLASS based on INITARGS.
CLASS is a class symbol. For example:
INITARGS is a property list with keywords based on the :initarg
for each slot. For example:
(make-instance 'foo :slot1 value1 :slotN valueN)
If the first element of INITARGS is a string, it is used as the
name of the class.
In EIEIO, the class' constructor requires a name for use when printing.
`make-instance' in CLOS doesn't use names the way Emacs does, so the
class is used as the name slot instead when INITARGS doesn't start with a string.