* [service] Restart SwSS Docker container if orchagent exits unexpectedly
* Configure systemd to stop restarting swss if it attempts to restart more than 3 times in 20 minutes
* Move supervisor-proc-exit-listener script
* [docker-dhcp-relay] Enhance wait_for_intf.sh.j2 to utilize STATEDB
* Ensure dependent services stop/start/restart with SwSS
* Change 'StartLimitInterval' to 'StartLimitIntervalSec', as Stretch installs systemd 232 (>= v230)
* Also update journald.conf options
* Remove 'PartOf' option from unit files
* Add '$(SUPERVISOR_PROC_EXIT_LISTENER_SCRIPT)' to new shared docker-orchagent makefile
* Make supervisor-proc-exit-listener script read from 'critical_processes' file inside container
* Update critical_processes file for swss container
* [DHCP Relay]: Support new <DhcpRelays> minigraph tag; support multiple VLANs
* Don't start dhcrelay in quiet mode so as to get startup output in syslog
* Update sonic-cfggen tests to support new '<DhcpRelays>' tag
* <DhcpRelays> tag is only present for VLANs which require a DHCP relay agent -- only parse if present
* Don't attempt to configure a DHCP relay agent for VLANs without specified DHCP servers
* Modify to work with Taoyu's minigraph/DB changes (#942)
* Reduce number of DHCP servers in sonic-cfggen unit tests from 4 to 2
* Remove isc-dhcp-relay sample output file from sonic-cfggen test, as we no longer generate that file
* Update Option 82 isc-dhcp-relay patch to load all interface name-alias maps into memory once at start instead of calling sonic-cfggen on each packet we relay
* Remove executable permission from Jinja2 template
* Set max hop count to 1 so that DHCP relay will only relay packets with a hop count of zero
* Replace tabs with spaces
* Modify overlooked sonic-cfggen call, use Config DB instead of minigraph
* Also ensure > 1 VLAN requires a DHCP relay agent before outputting to template
* Generate port name-alias map file using sonic-cfggen and parse that in lieu of parsing port_config.ini directly
* No longer drop packets with hop count > 0; Instead, drop packets which already contain agent info
Modify minigraph parser output format so it fit DB schema
Modify configuration templates to fit new schema
Systemd services dependencies are modified so database starts before any configuration consumer
