In contact list and conversation screen's header, display real profile
image loaded for each contact.

Add TestAvatarCreator implementation that adds random avatar images for
testing contacts.

Nico authored 3 years ago and Sebastian committed 3 years ago

Kudos to @sebkur

Because the MessageTracker in briar initializes the GroupCount timestamp
to the current time when the contact is being added, we cannot have
realistic test data in the database where the GroupCount timestamp
matches that of the last message in the chat history. This is a dirty
workaround to make this possible.