Exceptions: Failure, InvalidNumber
+sendPaymentNotification(receipt<ay>, note<s>, recipient<s>) -> timestamp<x>::
+* receipt : Byte array with the payment receipt blob
+* note : String with a note for the payment
+* recipient : String with the phone number of a single recipient
+
+* timestamp : Long, can be used to identify the corresponding Signal reply
+
+Exceptions: Failure
+
sendNoteToSelfMessage(message<s>, attachments<as>) -> timestamp<x>::
* message : Text to send (can be UTF8)
* attachments : String array of filenames to send as attachments (passed as filename, so need to be readable by the user signal-cli is running under)