Bug fix and minor improvements

Improvements:
- Add instant feedback upon setting a different
  presence for account (local echo)
- Sort room members by power level and then
  presence
- Periodically update members' `last_acitve_at`
  field on the room pane
- Move status message field up on account context
  menu, and put invisible before offline again

Bug fix:
- Do not try to override presence set from
  another client, accept it

src/gui/Base/HUserAvatar.qml

@@ -71,12 +71,13 @@ HAvatar {
             anchors.bottom: parent.bottom
             anchors.right: parent.right
             radius: diameter / 2
+            opacity: presence.includes("echo") ? 0.4 : 1
 
             color:
-                presence === "online" ?
+                presence.includes("online") ?
                 theme.controls.presence.online :
 
-                presence === "unavailable" ?
+                presence.includes("unavailable") ?
                 theme.controls.presence.unavailable :
 
                 theme.controls.presence.offline
@@ -84,6 +85,9 @@ HAvatar {
             border.color: theme.controls.presence.border
             border.width: diameter / 10
 
+            Behavior on color   { HColorAnimation {} }
+            Behavior on opacity { HNumberAnimation {} }
+
             HoverHandler { id: presenceHover }
 
             HToolTip {