Augment README of pynx584

[mikegwatson]

Below are the security system settings I used to get everything working:

Recommended Panel configuration settings:

   - Protocol: ASCII

   - Speed: 38400 Baud (OR WHICHEVER YOU CHOOSE)

   - Enabled Transition Messages:
             * Interface Configuration Message
             * Zone Status Message
             * Partition Status Message
             * System Status Message
             * Log Event Message
             * Keypad Message Received (OPTIONAL)
             * X-10 Message Received (OPTIONAL)

   - Enabled Commands:
             * Interface Configuration Request
             * Zone Name Request
             * Zone Status Request
             * Zones Snapshot Request
             * Partition Status Request
             * Partitions Snapshot Request
             * Send X-10 Message (OPTIONAL)
             * Log Event Request
             * Send Keypad Text Message (OPTIONAL)
             * System Status Request
             * Program Data Request (OPTIONAL)
             * Program Data Command (OPTIONAL)
             * Set Clock / Calendar Command
             * Primary Keypad Function with PIN (OPTIONAL)
             * Secondary Keypad Function (OPTIONAL)
             * Zone Bypass Toggle (OPTIONAL)

To autostart the nx584_server on boot, as user pi, I edited /etc/rc.local to include the following line before exit 0: sudo su - pi -c '/usr/local/bin/nx584_server --serial /dev/ttyUSB1 --baud 38400' &