🖨 Override print only in debug builds

[chris-araman]

Unfortunately, the hack for OutputListener broke clearLine and color output. We don't have a way to pass the variadic arguments directly to Swift.print due to a language limitation.

This change fixes progress output from mas upgrade and color output from printInfo, printWarning, and printError. Additionally, we now override print only for debug builds.

I've verified line clearing and color output by inserting the following into OutdatedCommand:

        print("Downloading foo", terminator: "")
        clearLine()
        print("Downloading bar", terminator: "")
        clearLine()
        print("Downloading baz")
        printInfo("Complete")