Make shiny frequency curves run as a proper R demo

Change-Id: I75dbfd97c98cd586f012e4d6409ed71d7745a201
diff --git a/.Rbuildignore b/.Rbuildignore
index c5d51fc..b0160d1 100644
--- a/.Rbuildignore
+++ b/.Rbuildignore
@@ -8,3 +8,4 @@
 ^docs$
 ^_pkgdown\.yml$
 ^CRAN-RELEASE$
+^.*\.log$