Fix a bug that utility.isNote does not handle symlinks properly

lib/notational-velocity.coffee

@@ -73,8 +73,8 @@ module.exports =
   autodelete: (paneItem) ->
     return false unless paneItem?.getURI?()?
     uri = paneItem.getURI()
-    return unless Utility.isNote(uri)
-    return false unless paneItem?.isEmpty()
+    return false unless Utility.isNote(uri)
+    return false unless paneItem.isEmpty()
     fs.unlinkSync(uri)
     noteName = uri.substring(@rootDirectory.length + 1)
     atom.notifications.addInfo("Empty note #{noteName} is deleted.")

lib/utility.coffee

@@ -11,7 +11,16 @@ class Utility
   @getPrimaryNoteExtension: -> if atom.config.get('nvatom.extensions').length then atom.config.get('nvatom.extensions')[0] else '.md'
 
   @isNote: (filePath) ->
+    return false unless path.extname(filePath) in atom.config.get('nvatom.extensions')
+
     filePath = fs.normalize(filePath)
-    return filePath.startsWith(Utility.getNoteDirectory()) and path.extname(filePath) in atom.config.get('nvatom.extensions')
+    return true if filePath.startsWith(Utility.getNoteDirectory())
+    return true if filePath.startsWith(fs.realpathSync(Utility.getNoteDirectory()))
+    return false unless fs.existsSync(filePath)
+
+    filePath = fs.realpathSync(filePath)
+    return true if filePath.startsWith(Utility.getNoteDirectory())
+    return true if filePath.startsWith(fs.realpathSync(Utility.getNoteDirectory()))
+    return false
 
   @trim: (str) -> str?.replace /^\s+|\s+$/g, ''