fix: wallet coin selection respects max_block_weight (#2546)

* fix #2510: wallet coin selection respects max_block_weight

Deprecate "soft" max_outputs limit and introduce "hard" max_outputs
limit based on max_block_weight.

* Fix tests

src/bin/cmd/wallet_args.rs

@@ -389,9 +389,6 @@ pub fn parse_send_args(args: &ArgMatches) -> Result<command::SendArgs, ParseErro
 	// fluff
 	let fluff = args.is_present("fluff");
 
-	// max_outputs
-	let max_outputs = 500;
-
 	Ok(command::SendArgs {
 		amount: amount,
 		message: message,
@@ -402,7 +399,6 @@ pub fn parse_send_args(args: &ArgMatches) -> Result<command::SendArgs, ParseErro
 		dest: dest.to_owned(),
 		change_outputs: change_outputs,
 		fluff: fluff,
-		max_outputs: max_outputs,
 	})
 }