Fix some CRAN policy issues

Change-Id: I6862ea1bfbadbaf5d6090b6655c21ecf66650c16
diff --git a/demo/regional.R b/demo/regional.R
index cf31ab7..10b5f82 100755
--- a/demo/regional.R
+++ b/demo/regional.R
@@ -1,7 +1,7 @@
 #!/usr/bin/Rscript
 library(RKorAPClient)
 library(ggplot2)
-library(sf)
+## sf is used via sf::; don't attach package in demo to avoid undeclared library() calls
 # library(R.cache)
 
 devAskNewPage(ask = FALSE)