fix lexer/parser bugs, add code in file-thread.sml to handle loading/saving of files (but loading is not completely finished yet)

fcore/parser/int-dfa.sml

@@ -8,12 +8,10 @@ struct
     let
       val chr = Char.chr i
     in
-      if chr >= #"0" orelse chr < #"9" then
-        final
-      else dead
+      if Char.isDigit chr then final else dead
     end
 
-  val deadTable = SpaceDfa.deadTable
+  val deadTable = Vector.tabulate (255, fn _ => dead)
   val startTable  = Vector.tabulate (255, makeStart)
   val finalTable = startTable