Be smarter about when to send lock codes

The fall back message containing the lock code (that cannot be customized) sends automatically at check in time unless a message has automatically been sent that contains the %smartlock_code% short code; however, not all messages with guest are automatic. If a guest asks me for their code before the automatic message and I reply to them, they still receive the very impersonal fall back message at check in time. It does not make for a good user experience. Your system should look through the message history to see if the actual lock code was sent, not just search the automated messages for the short code.