support historical abci queries (Refs #482)

rpc/client/types.go

@@ -0,0 +1,13 @@
+package client
+
+// ABCIQueryOptions can be used to provide options for ABCIQuery call other
+// than the DefaultABCIQueryOptions.
+type ABCIQueryOptions struct {
+	Height uint64
+	Prove  bool
+}
+
+// DefaultABCIQueryOptions are latest height (0) and prove equal to true.
+func DefaultABCIQueryOptions() ABCIQueryOptions {
+	return ABCIQueryOptions{Height: 0, Prove: true}
+}