[BREAKING] ae.utils.funopt: Be case sensitive by default

Rationale:

- The old behavior was accidental.

- This prevented specifying options / switches that differ only by
  name, e.g. -f / -F.

Changes required:

- If users of your ae.utils.funopt program relied on case
  insensitivity of option or switch names, the old behavior can be
  restored by explicitly specifying config.caseInsensitive.

utils/funopt.d

@@ -254,6 +254,7 @@ if (isCallable!FUN)
 
 	getopt(args,
 		std.getopt.config.bundling,
+		std.getopt.config.caseSensitive,
 		getOptArgs.tupleof,
 		"h|help", &help,
 	);