fix: isprint => canprint

add a canprint() func that return true iif
char is ascii (< 0x80) and not a control char
(> 0x1F), as isprint() seems to be different
under Linux and Windows

misc.c

@@ -22,6 +22,11 @@
 
 #include "dvdisaster.h"
 
+int canprint(char c)
+{
+   return ((isascii(c) && !iscntrl(c)) ? 1 : 0);
+}
+
 /***
  *** gettext() convenience
  ***/