More refactoring for a standalone version of Closure HTML.

More refactoring for a standalone version of Closure HTML.

	* src/glisp/util.lisp (G/READ-BYTE-SEQUENCE): Call
	cl:read-sequence instead of the old portability functions
	glisp:read-byte-sequence, which Closure HTML will not use any
	more.  (GSTREAM-AS-STRING): Ditto for cl:make-array and
	glisp:g/make-string.

	* src/util/clex.lisp (DEFLEXER): cl:make-array instead of
	glisp:g/make-string as above.

	* src/parse/pt.lisp (ELEMENT-P, ELEMENT-PARENT, ELEMENT-CHILDREN,
	ELEMENT-ATTRIBUTE, ELEMENT-GI, TEXT-ELEMENT-P, ELEMENT-TEXT):
	Removed element protocol methods from Closure HTML, because the
	protocol (and these methods) will stay in Closure CVS.

	* src/parse/sgml-parse.lisp (SETUP-CODE-VECTOR): Use
	runes-encoding:find-encoding rather than cxml::find-encoding,
	because we depend only on closure-common, not on cxml.