Remove from list of illegal filename characters: [, ], +, and =.

[]+ are still illegal filename chars in Win95 VFAT, so Win9x sysops may beware.
= is a legal filename char in all modern file systems (after commodore 64).

src/sbbs3/sbbsdefs.h

@@ -65,7 +65,7 @@
 
 #define FNOPEN_BUF_SIZE		(2*1024)
 
-#define ILLEGAL_FILENAME_CHARS	"\\/|<>+[]:=\";,%"
+#define ILLEGAL_FILENAME_CHARS	"\\/|<>:\";,%"
 
 #define BIND_FAILURE_HELP	"!Another application or service may be using this port"
 #define UNKNOWN_LOAD_ERROR	"Unknown load error - Library mismatch?"