scrapyd-client doesn't accept target name, like scrapyd-deploy

[jpmckinney]

scrapyd-client -t <target> <command> <options>

target here needs to be a base URL. With scrapyd-deploy, it is instead the name of the target in the configuration file.

I don't see the point in allowing target to be an arbitrary URL. It's extra typing for the use case of a target defined in the configuration file.