Add 'zcash_history/' from commit 'e2c131fdc308265adcab774e54d4d5804c23b368'

git-subtree-dir: zcash_history
git-subtree-mainline: be0ee9eb82
git-subtree-split: e2c131fdc3

zcash_history/examples/lib/main.rs

@@ -0,0 +1,4 @@
+// dummy example
+pub fn main() {
+
+}