Support MetaEvents::Tracker overriding the external name used for events
Update documentation to describe the new default_external_name feature
Support custom external names for events via the :external_name option
Update readme to include information about overriding external event names
As early as posssible, validate external_name overrides respond to #call
Only validate default_external_name responds to :call if one was provided
Convert to using external_name for all external event names, as an explicit feature
Separate expecting a defined event from expecting a defined event that has a custom external name
Merge pull request #3 from aaronlerch/feature/friendly_names

Allow overriding of the `external_name` sent to analytics backends