Refactor Avatar and AvatarOverlay to have 'account' as prop instead of src and staticSrc (#4526)

* Refactored Avatar and AvatarOverlay (DRY) to have 'account' as prop.
Also removed animate attribute from compose navigation bar, which should
have never been there. Added test for avatar overlay.

* fix broken tests

* god dammit another bug in tests! travis please let this pass

* formatting in avatar overlay

app/javascript/mastodon/features/compose/components/autosuggest_account.js

@@ -15,7 +15,7 @@ export default class AutosuggestAccount extends ImmutablePureComponent {
 
     return (
       <div className='autosuggest-account'>
-        <div className='autosuggest-account-icon'><Avatar src={account.get('avatar')} staticSrc={account.get('avatar_static')} size={18} /></div>
+        <div className='autosuggest-account-icon'><Avatar account={account} size={18} /></div>
         <DisplayName account={account} />
       </div>
     );