revert exists(), unused

util.go

@@ -33,15 +33,6 @@ func contains(s []string, e string) bool {
 	return false
 }
 
-func exists(m map[string]interface{}, item string) bool {
-	// FIXME: try to use this for all cases
-	if _, ok := m[item]; ok {
-		return true
-	}
-
-	return false
-}
-
 func const2num(name string) float64 {
 	switch name {
 	case "Pi":