Can't mention yourself in teams

[robmoffat]

You can't do @robmoffat if you are @robmoffat , you can only mention other people.

This is annoying in say, the todo bot, because I can't assign items to myself.

Idea: be able to type @me, and have the parser figure out who it is.

[robmoffat]

@vaibhav-db to see if this is still the case