Disable buffer modified indicator if buffer content matches content on disk

src/app/buffer.coffee

@@ -248,6 +248,9 @@ class Buffer
   isModified: ->
     @modified
 
+  contentDifferentOnDisk: ->
+    fs.read(@file.getPath()) != @getText()
+
   getAnchors: -> new Array(@anchors...)
 
   addAnchor: (options) ->

src/app/status-bar.coffee

@@ -33,7 +33,8 @@ class StatusBar extends View
     @editor.getBuffer().on 'buffer-change', => @updateBufferModifiedText()
 
   updateBufferModifiedText: ->
-    if @editor.getBuffer().isModified()
+    buffer = @editor.getBuffer()
+    if buffer.isModified() and buffer.contentDifferentOnDisk()
       @bufferModified.text('*')
     else
       @bufferModified.text('')