Ensure always on set by sidebar state

Refactored the way changing the tool triggers setting visible highlights.
The change should always ensure better interaction if other components
change the tool or highlight state in the future and trigger events.

h/js/guest.coffee

@@ -7,6 +7,8 @@ class Annotator.Guest extends Annotator
     ".annotator-adder button mousedown": "onAdderMousedown"
     ".annotator-hl mousedown": "onHighlightMousedown"
     ".annotator-hl click": "onHighlightClick"
+    "setTool": "onSetTool"
+    "setVisibleHighlights": "onSetVisibleHighlights"
 
   # Plugin configuration
   options:
@@ -115,7 +117,7 @@ class Annotator.Guest extends Annotator
     )
 
     .bind('setVisibleHighlights', (ctx, state) =>
-      this.setVisibleHighlights state
+      this.setVisibleHighlights state, false
       this.publish 'setVisibleHighlights', state
     )
 
@@ -224,24 +226,17 @@ class Annotator.Guest extends Annotator
       method: 'setTool'
       params: name
 
-    switch name
-      when 'comment'
-        this.setVisibleHighlights this.visibleHighlights, true
-      when 'highlight'
-        this.setVisibleHighlights true, true
-
-  setVisibleHighlights: (state=true, temporary=false) ->
-    unless temporary
-      @visibleHighlights = state
+  setVisibleHighlights: (state=true, notify=true) ->
+    if notify
       @panel?.notify
         method: 'setVisibleHighlights'
         params: state
-
-    markerClass = 'annotator-highlights-always-on'
-    if state or (@tool is 'highlight')
-      @element.addClass markerClass
     else
-      @element.removeClass markerClass
+      markerClass = 'annotator-highlights-always-on'
+      if state or this.tool is 'highlight'
+        @element.addClass markerClass
+      else
+        @element.removeClass markerClass
 
   addComment: ->
     sel = @selectedRanges   # Save the selection
@@ -318,3 +313,14 @@ class Annotator.Guest extends Annotator
 
     # Display the editor.
     this.showEditor(annotation, position)
+
+  onSetTool: (name) ->
+    switch name
+      when 'comment'
+        this.setVisibleHighlights this.visibleHighlights, false
+      when 'highlight'
+        this.setVisibleHighlights true, false
+
+  onSetVisibleHighlights: (state) =>
+    this.visibleHighlights = state
+    this.setVisibleHighlights state, false
\ No newline at end of file