Remove Add() function from accumulator

accumulator.go

@@ -6,11 +6,6 @@ type Accumulator interface {
 	// Create a point with a value, decorating it with tags
 	// NOTE: tags is expected to be owned by the caller, don't mutate
 	// it after passing to Add.
-	Add(measurement string,
-		value interface{},
-		tags map[string]string,
-		t ...time.Time)
-
 	AddFields(measurement string,
 		fields map[string]interface{},
 		tags map[string]string,