Early read receipts should start expiration timers
Early read receipts should start expiration timers

Check for early read receipts for an incoming messages *after*
processing the expireTimer on that message. Then we can set
expirationStartTime appropriately if an early receipt is found.

Closes #950

// FREEBIE

nrizzio/Signal-Desktop,nrizzio/Signal-Desktop,nrizzio/Signal-Desktop,nrizzio/Signal-Desktop