Overall += Add{OK,Warning,Critical,Unknown}

The current Add() requires the user to manually access the defined
constants for OK, Warning, Critical, and Unknown.

The four new methods to not require the use to manually specify them.

result/overall.go

@@ -16,6 +16,22 @@ type Overall struct {
 	Outputs   []string
 }
 
+func (o *Overall) AddOK(output string) {
+	o.Add(check.OK, output)
+}
+
+func (o *Overall) AddWarning(output string) {
+	o.Add(check.Warning, output)
+}
+
+func (o *Overall) AddCritical(output string) {
+	o.Add(check.Critical, output)
+}
+
+func (o *Overall) AddUnknown(output string) {
+	o.Add(check.Unknown, output)
+}
+
 func (o *Overall) Add(state int, output string) {
 	switch state {
 	case check.OK: