app tweaks - times, version and ack ticks

[nanometrenat]

Using the app in the field we identified a few minor things that could do with improvement when time permits:

1. in feed and inbox, what time does the time shown against a message represent? time on the sending user's handset? time received by a ME? time received on recipient's handset? We saw a number of cases where times were way out of what we expect (e.g. different years) so need to show onscreen a label to clarify what this time refers to.
   NB as the chat app is often used by devices out of cellular coverage the handset time is not automatically derived from network time - and out-of-the-box phone times are never correct.
2. it would be ideal to show app version within the app for easy troubleshooting (rather than having to go outside the app, to Android's settings/app info)
3. ack ticks don't seem consistent - sometimes receive two ticks a message apart etc. - needs further testing.

Feel free to split to separate tickets if preferred.