more precise treatment of \r\n as blank symbol (cf. 2bf29095d26f), e.g. relevant for loading theory headers in Isabelle/jEdit -- NB: jEdit and Isabelle/ML normalize newline variants to \n, but Isabelle/Scala retains them literally;

--- a/src/Pure/General/symbol.scala	Mon Mar 26 19:18:03 2012 +0200
+++ b/src/Pure/General/symbol.scala	Mon Mar 26 20:42:00 2012 +0200
@@ -347,7 +347,7 @@
       "\\<^isub>", "\\<^isup>")
 
     val blanks =
-      recode_set(space, "\t", "\n", "\u000B", "\f", "\r", "\\<spacespace>", "\\<^newline>")
+      recode_set(space, "\t", "\n", "\u000B", "\f", "\r", "\r\n", "\\<spacespace>", "\\<^newline>")
 
     val sym_chars =
       Set("!", "#", "$", "%", "&", "*", "+", "-", "/", "<", "=", ">", "?", "@", "^", "_", "|", "~")