When the timeline recognize last message and current user will change behavior

[horacioibrahim]

For each message the avatar from user that posted is displayed but when the same user posts sequencial messages is not necessary show the avatar for each new message.

Current implementation:

[||] A comment is posted where `[||]`
is an avatar
[||] This is second comment that shows
the avatar.

Future:

[||] A comment is posted where `[||]`
is an avatar
This is second comment that NOT shows
the avatar.