Payment Proof export + validation (#289)

* add payment proof struct and deser

* rustfmt

* adding proof export functions

* rustfmt

* add payment proof validation function

* rustfmt

* add RPC version of retrieve_payment_proof + doctest

* rustfmt

* add verify_proof rpc function and documentation for new functions

* rustfmt

* add export and verify commands

* rustfmt

* test + test framework fixes

* rustfmt

* check whether addresses belong to this wallet, output such when checking

* rustfmt

* remove raw pubkey address and replace with ov3 address in user-facing contexts

* merge from master and rustfmt

* doctests

impls/src/test_framework/testclient.rs

@@ -353,7 +353,15 @@ where
 		let max = split[2].parse::<u64>().unwrap();
 		let commit_bytes = util::from_hex(excess).unwrap();
 		let commit = pedersen::Commitment::from_vec(commit_bytes);
-		let k = super::get_kernel_local(self.chain.clone(), &commit, Some(min), Some(max));
+		let min = match min {
+			0 => None,
+			m => Some(m),
+		};
+		let max = match max {
+			0 => None,
+			m => Some(m),
+		};
+		let k = super::get_kernel_local(self.chain.clone(), &commit, min, max);
 		Ok(WalletProxyMessage {
 			sender_id: "node".to_owned(),
 			dest: m.sender_id,