[RFE] Disallow spaces in the command parameter

This would enforce the usage of the :params when needed, and a user would not be able to bypass it. If they are going to bypass anyway, then there is no point in using AwesomeSpawn.

The only use case we might have to account for is sudo. I say might, because one case easily do

AwesomeSpawn.run!("sudo", :params => ["echo", "hi")

But that is kind of weird. I think I'd prefer another param:

AwesomeSpawn.run!("echo", :params => "hi", :sudo => true)
AwesomeSpawn.run!("echo", :params => "hi", :sudo => "someuser")

Which would be nice because a caller could build the options and call it, then on failure just tack in another option (instead of having to re-call AwesomeSpawn and reorder all of the params.

Start at the AwesomeSpawn.run! entry point and trace how its command and params arguments are handled. Clarify whether the requested change is only rejecting spaces in the command or also adding sudo support, then define tests for the accepted and rejected forms before implementation.