Rmk143 INITVARS command for MEDLEY-INIT-VARS, FLUSHFONTCACHE (#2383)

* loadup scripts:  set MEDLEY-INIT-VARS to NOBIND before loading MEDLEYDIR
so that INITVARS in MEDLEYDIR replaces any previous settings in the loadup-sysout

* FONT:  add cache for FONTSAVAILABLE, add FLUSHFONTCACHE.  See FONTCODECHANGES.tedit

* Make FONTEXISTS and FONTSAVAILABLE consistent

scripts/loadups/loadup-init.sh

@@ -11,6 +11,7 @@ main() {
 	(* "make init files; this file is loaded as a 'greet' file by scripts/loadup-init.sh")
 
 	(SETQ MEDLEYDIR NIL)
+	(SETATOMVAL (QUOTE MEDLEY-INIT-VARS) (QUOTE NOBIND))
 	(LOAD (CONCAT (UNIX-GETENV "MEDLEYDIR") "/sources/MEDLEYDIR.LCOM"))
 	(MEDLEY-INIT-VARS)
 	(PUTASSOC (QUOTE MEDLEY) (LIST (UNIX-GETENV (QUOTE LOADUP_COMMIT_ID))) SYSOUTCOMMITS)

scripts/loadups/loadup-lisp-from-mid.sh

@@ -12,6 +12,7 @@ main() {
 
 	(PROGN
           (SETQ LOADUP-SUCCESS NIL)
+	  (SETATOMVAL (QUOTE MEDLEY-INIT-VARS) (QUOTE NOBIND))
 	  (LOAD (CONCAT (QUOTE {DSK}) (UNIX-GETENV (QUOTE MEDLEYDIR)) (QUOTE /sources/MEDLEYDIR.LCOM)))
 	  (MEDLEY-INIT-VARS)
 	  (LOAD (CONCAT (QUOTE {DSK}) (UNIX-GETENV (QUOTE LOADUP_SOURCEDIR)) (QUOTE /LOADUP-LISP.LCOM)))