Support an -r shortcut for --release in ./x.rs

[tcr]

It's a lot of work to type ./x.rs server --client-proxy --release in one window and ./x.rs client-proxy --release in another!

-r would allow this to shorten to ./x.rs server -cr and ./x.rs client-proxy -r.

Because this has to be handled at the x.rs (not the shelled out binary) level, this needs special logic to detect the short argument.

[tcr]

./x.rs needs to stop passing arguments to subcommands and instead have knowledge of all of them itself. It's a script runner, not a glorified way to invoke binaries.

[tcr]

Depends on #60.