Add mosaicplot demo

Change-Id: I43ae73b97ac2f6989ec1111a53302878aca72045
diff --git a/demo/00Index b/demo/00Index
index 7fe8aff..b954748 100644
--- a/demo/00Index
+++ b/demo/00Index
@@ -3,3 +3,4 @@
 conditionsOverTime        Plot frequency of query expressions over time under different conditions
 alternativesOverTime      Plot proportion of alternative spellings/variants over time
 regional                  Map plot regional frequencies of query expression
+mosaicplot                Visualize frequencies of alternative query terms in relation to other variables