amendments to car rental booking system

- request read receipt upon sending confirmation/rejection email - ability to cancel a confirmed booking - ability to resend confirmation/rejection email - be able to choose which template email to use when sending out emails to clients (and be able to edit this) - have correct damage liability automatically calculated for the vehicle & level of insurance the client chooses -and include this info in the confirmation/rejection email - choose set special rates if booking selected in quiet periods - currently, if credit card expires in current month, client is not allowed to make a booking - this needs to be changed