Late locking (experimental) (#530)

* Late locking (experimental)

* Error on fee change

* Improve comments

* Fix typo in comment

* Add late locking flag to CLI command

src/bin/grin-wallet.yml

@@ -112,6 +112,10 @@ subcommands:
             help: Estimates all possible Coin/Output selection strategies.
             short: e
             long: estimate-selection
+        - late_lock:
+            help: EXPERIMENTAL - Do not lock the coins immediately, instead only lock them during finalization.
+            short: l
+            long: late-lock
         - change_outputs:
             help: Number of change outputs to generate (mainly for testing)
             short: o

src/cmd/wallet_args.rs

@@ -479,6 +479,8 @@ pub fn parse_send_args(args: &ArgMatches) -> Result<command::SendArgs, ParseErro
 	// estimate_selection_strategies
 	let estimate_selection_strategies = args.is_present("estimate_selection_strategies");
 
+	let late_lock = args.is_present("late_lock");
+
 	// dest
 	let dest = match args.value_of("dest") {
 		Some(d) => d,
@@ -533,6 +535,7 @@ pub fn parse_send_args(args: &ArgMatches) -> Result<command::SendArgs, ParseErro
 		minimum_confirmations: min_c,
 		selection_strategy: selection_strategy.to_owned(),
 		estimate_selection_strategies,
+		late_lock,
 		dest: dest.to_owned(),
 		change_outputs: change_outputs,
 		fluff: fluff,