Presence: add some notes about what not to refactor
Presence: add some notes about what not to refactor

I keep looking at this code and thinking it should be shared with other
code in this file and then re-discovering why not…

jku/telepathy-gabble,Ziemin/telepathy-gabble,Ziemin/telepathy-gabble,jku/telepathy-gabble,mlundblad/telepathy-gabble,Ziemin/telepathy-gabble,mlundblad/telepathy-gabble,mlundblad/telepathy-gabble,Ziemin/telepathy-gabble,jku/telepathy-gabble