update README for new approach to variable substitution
update README for new approach to variable substitution

drostron/quasar,jedesah/Quasar,quasar-analytics/quasar,jedesah/Quasar,slamdata/slamengine,djspiewak/quasar,slamdata/slamengine,jedesah/Quasar,wemrysi/quasar,wemrysi/quasar,drostron/quasar,drostron/quasar,slamdata/slamengine,slamdata/quasar,jedesah/Quasar,quasar-analytics/quasar,drostron/quasar,quasar-analytics/quasar,quasar-analytics/quasar