My team spent a bit of time debugging a mistake where we forgot to
redirect output to a file. The command looked valid and exited 0. This
change causes the program to fail if provided with any positional
arguments.
Makes it so that the value of the "go.version" property in
the output XML can be customized by the caller using the
"go-version" flag. If the flag is unspecified, falls back to
the previous behavior of using runtime.Version() as the value.
Fixes#48