first commit status: option and argument parsing, short aliases grouping, special values, hidden options

Option types: bool int, int-array, string, string-array, string-map, file, dir

opt-manager.go

@@ -0,0 +1,10 @@
+package cli
+
+func (cli *CliParser) SetOptionValue(name string, value string) (err error) {
+	if opt := cli.findOptionByArg(name); opt != nil {
+		_, err = opt.parse(cli, -1, &value)
+	} else {
+		err = errOptionNotFound(name)
+	}
+	return
+}