Targets need a field for supplemental data
I'm not quite sure how to implement this yet, but with the django templates being used for mail content (
#5), we need a way to populate some kind of extra_context dict per-target.
This will allow us to substitute in things like the target's first/last name, if that data is available. Static values only -- I don't want to be eval datetime objects or anything like that.
Perhaps there's some kind of dict-field that I can use for this... research required.