support array in chalkboard reveal_options (#88)

fixes #62

Co-authored-by: christophe dervieux <christophe.dervieux@gmail.com>
diff --git a/tests/manual/.gitignore b/tests/manual/.gitignore
new file mode 100644
index 0000000..3c10755
--- /dev/null
+++ b/tests/manual/.gitignore
@@ -0,0 +1,2 @@
+*_files
+*.html