Suggestion: provide an `eval` option for implicit expression output, as in the REPL

The implicit output of expression results in the REPL is a great feature that obviates the need for Console.WriteLine() (and even does a better job at creating meaningful output than straight .ToString() stringification).

Especially for presumably typically short code passed to dotnet-script eval, it would be handy to have automatic result printing as well, so that instead of:

dotnet-script eval "Console.WriteLine(1+2)"

you could simply write something like:

dotnet-script eval "1+2"  -p

and have 3 automatically printed.