Added new RecordCustomMetric method to Application. This functionality can be used to track averages or counters without using custom events. See Custom Metric Documentation
Fixed import needed for logrus. The import Sirupsen/logrus had been renamed to sirupsen/logrus. Thanks to @alfred-landrum for spotting this.
Added ErrorAttributer, an optional interface that can be implemented by errors provided to Transaction.NoticeError to attach additional attributes. These attributes are subject to attribute configuration.
Added Error, a type that allows direct control of error fields.