Don't emit BS when at beginning of input buffer

blk/427

@@ -1,10 +1,10 @@
 ( handle backspace: go back one char in IN>, if possible, then
-  emit SPC + BS )
+  emit BS + SPC + BS )
 : (inbs)
     ( already at IN( ? )
     IN> @ IN( = IF EXIT THEN
     IN> @ 1- IN> !
-    SPC BS
+    BS SPC BS
 ;
 
 : KEY

blk/428

@@ -1,12 +1,12 @@
-: (rdlnc)                   ( -- f )
+: (rdlnc) ( -- c )
     ( buffer overflow? same as if we typed a newline )
     IN> @ IN) = IF 0x0a ELSE KEY THEN ( c )
     DUP 0x7f = IF DROP 0x8 THEN ( del? same as backspace )
     DUP 0x0a = IF DROP 0xd THEN ( lf? same as cr )
-    ( echo back )
-    DUP EMIT                    ( c )
     ( bacspace? handle and exit )
     DUP 0x8 = IF (inbs) EXIT THEN
+    ( echo back )
+    DUP EMIT ( c )
     ( write and advance )
     DUP ( keep as result ) ( c c )
 ( We take advantage of the fact that c's MSB is always zero and