Simple Assets v1.5.2

• Re-enabled event notifications for the following actions:
  saeburn, saeclaim, saetransfer, saechauthor, saecreate.
  Changed notification logic.
  If an author's contract needs to be notified about changes in scope of an asset, please see this example:
  https://github.com/CryptoLions/SimpleAssets-EventReceiverExample