* FEATURE: Don't display muted/ignored users under "who liked"
Previously, if you clicked on the heart icon below a post
it would show you the avatar for a user even if you ignored or muted
them.
This commit will instead display a (?) icon. The count of likes will
remain correct, but you needn't be reminded of the person you
preferred not to see.
* Use a circle instead of (?) for unknown user
This reduces chances of errors where consumers of strings mutate inputs
and reduces memory usage of the app.
Test suite passes now, but there may be some stuff left, so we will run
a few sites on a branch prior to merging
