Change annotation card focusing implementation

So that
 - Instead of a map, we now store a list of focused tags
 - The check for being focused has been moved
   into a method in the controller
 - The sidebar now exepts simply a list of tags to
   focus on (no more add/remove tags to existing list)

h/static/scripts/controllers.coffee

@@ -358,6 +358,8 @@ class ViewerController
       else
         true
 
+    $scope.isFocused = (annotation) ->
+      annotation?.$$tag in ($scope.focusedAnnotations ? [])
 
 angular.module('h')
 .controller('AppController', AppController)

h/static/scripts/guest.coffee

@@ -250,12 +250,10 @@ class Annotator.Guest extends Annotator
       method: "showEditor"
       params: annotation.$$tag
 
-  focusInViewer: (annotations, state) =>
+  focusInViewer: (annotations) =>
     @panel?.notify
-      method: "setFocusState"
-      params:
-        tags: (a.$$tag for a in annotations)
-        state: state
+      method: "setViewerFocus"
+      params: (a.$$tag for a in annotations)
 
   onAnchorMousedown: ->
 
@@ -305,15 +303,14 @@ class Annotator.Guest extends Annotator
     if @visibleHighlights or @tool is 'highlight'
       event.stopPropagation()
       annotations = event.data.getAnnotations(event)
-      this.focusInViewer annotations, true
+      this.focusInViewer annotations
 
   # When leaving a highlight (with the cursor) in highlighting mode,
   # tell the sidebar to stop hiliting the relevant annotations
   onAnchorMouseout: (event) ->
     if @visibleHighlights or @tool is 'highlight'
       event.stopPropagation()
-      annotations = event.data.getAnnotations(event)
-      this.focusInViewer annotations, false
+      this.focusInViewer []
 
   # When clicking on a highlight in highlighting mode,
   # tell the sidebar to bring up the viewer for the relevant annotations

h/static/scripts/services.coffee

@@ -164,9 +164,9 @@ class Hypothesis extends Annotator
         this.updateViewer this._getLocalAnnotations(tags)
     )
 
-    .bind('setFocusState', (ctx, data) =>
+    .bind('setViewerFocus', (ctx, tags=[]) =>
       @element.scope().$apply =>
-        this.setViewerFocusState data.tags, data.state
+        this.setViewerFocus tags
     )
 
     .bind('toggleViewerSelection', (ctx, tags=[]) =>
@@ -236,15 +236,8 @@ class Hypothesis extends Annotator
     @_setSelectedAnnotations selected
     this
 
-  setViewerFocusState: (tags, state) ->
-    scope = @element.scope()
-    focused = scope.focusedAnnotations ?= {}
-    for tag in tags
-      if state
-        focused[tag] = true
-      else
-        delete focused[tag]
-    this
+  setViewerFocus: (tags) ->
+    @element.scope().focusedAnnotations = tags
 
   updateViewer: (annotations=[]) ->
     # TODO: re-implement

h/templates/client/viewer.html

@@ -34,7 +34,7 @@
     </span>
   </li>
   <li class="paper thread"
-      ng-class="{'card-emphasis': focusedAnnotations[child.message.$$tag]}"
+      ng-class="{'card-emphasis': isFocused(child.message)}"
       deep-count="count"
       thread="child" thread-filter
       thread-collapsed="!search.query"