Add rCharts demo using Highcharts

Change-Id: I4d348937b5db7888def2ccc763d9171de2cfbc46
diff --git a/NAMESPACE b/NAMESPACE
index 86db8dc..8a84580 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -12,6 +12,7 @@
 export(group_by)
 export(ipm)
 export(mutate)
+export(percent)
 export(queryStringToLabel)
 export(select)
 export(summarise)