use_travis to set build ignore. Don't need before_install anymore
diff --git a/.Rbuildignore b/.Rbuildignore
index 5219fdf..c7d1c3e 100644
--- a/.Rbuildignore
+++ b/.Rbuildignore
@@ -1,3 +1,5 @@
 ^.*\.Rproj$
 ^.*\.Rproj\.user$
 ^\.Rproj\.user$
+^images$
+^\.travis\.yml$